I'm doing engineering in the instance.

The main structure of node P3 is a three-story steel frame building with steel plates on the outside and concrete floor slabs inside. The first floor has been poured, the second floor is half poured, and the third floor only has formwork and no concrete.

Xie Chengzhou stood in the concrete area of ​​the P3 platform for about two minutes, scanning the internal structure of P3.

The density of steel maggots is higher than in P1 and P2, and this is where they are most concentrated. P3 has the largest steel structure area, the most dark areas, and the deepest part below the waterline, making it the area with the highest density of steel maggots on the entire construction site.

"Go in," he said, "walk on the concrete floor, not the steel plate."

He assessed the entrance: the entrance to P3 was a steel-framed doorway without a door. There were steel columns on both sides of the doorway and the ground was concrete. About three meters in, there was a staircase. The staircase was a steel structure, but the treads had a concrete layer about five centimeters thick, which should be sufficient to isolate the vibration transmission.

"The stair treads are made of concrete," he said, "but they are only a little thick. Walk lightly, don't run, and don't jump."

He went in first.

---

The interior of P3 was darker than the exterior. Natural light cut in obliquely through the gaps in the damaged outer steel plate, forming several beams of light on the ground. The beams contained dust, salt spray, and the damp, metallic smell that had accumulated in the enclosed space for a long time.

Xie Chengzhou stepped onto the concrete floor and felt the vibration: weaker than the steel plate, weaker than the outside, the partition effect was obvious.

He walked inside, reached the stairwell, and examined the stair treads: a concrete layer, about five centimeters thick, with cracks. These were shrinkage cracks caused by long-term load and temperature changes, not structural fractures, and the load-bearing capacity was still intact.

He went upstairs to the second floor.

Only half of the concrete floor slab on the second floor has been poured. The side closest to the outer wall of P3 is concrete, while the other half is formwork made of wood. Wood does not transmit vibrations.

He focused his gaze on the inner side of the second floor, deep within the area of ​​that half-wooden template, where there was something.

It's not a tool, not a material, but a metal container, about 20 centimeters square, with an oxide layer on the surface, but its shape is regular. It doesn't look like construction waste; it looks like it was just placed there by someone.

"Here," he said.

Wu Ming took two steps forward. "I'll go get it," he said.

"Wait a minute," Xie Chengzhou said, scanning the distribution of steel maggots on the second floor. "There are no steel maggots in the wooden template area, you can go now."

Wu Ming walked over and picked up the container. "It's very heavy," he said. "About three kilograms."

Xie Chengzhou took it, turned the container over, and glanced at the markings on the surface: it was a geometric pattern with simple lines, engraved on the metal surface, and it was the same system as the one he had seen on the signature of the #001 factory area report and on the #002 nameplate.

He mentally superimposed the three symbols and confirmed one thing: this was not a coincidence.

He put the container into the inside pocket of his coat. "Main mission complete," he said. "Go downstairs and evacuate."

---

The accident happened when they went downstairs.

It wasn't on the stairs, but at the bottom of the stairs. Old Chen's foot stepped into the gap between the last step and the concrete floor—the gap was about one centimeter wide and was the settlement joint between the stairs and the floor. When Old Chen stepped in, his ankle twisted, and he fell to the side. His right hand instinctively reached for the steel column next to him.

There were steel maggots on that steel pillar.

His right hand reached out and then immediately snapped away, but the contact had already occurred—his palm was cut three shallowly by the steel maggot's shell, and blood seeped out. He clenched his fist and didn't say a word.

"Hands," Xie Chengzhou said.

"It's alright," Old Chen said, "it's shallow."

He loosened his fist and opened his palm. Xie Chengzhou glanced at it: three cuts, the deepest being about two millimeters deep. There was no contact with the secretions of the steel maggots; it was just a physical scratch on the outer shell, not corrosive.

"Can you walk?" Xie Chengzhou asked.

"Yes," Old Chen said. "Let's go."

They walked towards Exit P3, with Xie Chengzhou in the lead and Lao Chen in the third, his right hand clasped as he walked, without complaining.

Then the buzzing sound appeared.

It wasn't coming from beneath their feet, but from the direction of the P3 exit—the exit being that steel-framed doorway, outside which was the steel plate area of ​​the P3 platform. The buzzing came from that direction, low and dense, not a warning-level buzzing, but a resonance that had already gathered to a considerable extent.

Xie Chengzhou stopped at the exit and glanced outside.

On the steel plate of the P3 platform, within a range of about three meters outside the exit, there was a dense swarm of steel maggots.

Not a dozen, not twenty, but a number he hadn't anticipated at all before entering P3—dozens, perhaps more. Their rusty red and dark gray bodies overlapped, forming a two-centimeter-thick layer on the steel plate surface, like a moving rust, completely blocking the route to the concrete safety zone outside the exit area.

Xie Chengzhou quickly assessed in his mind: when they entered P3, the vibrations on the platform—walking, going upstairs, picking up objects—these accumulated vibrations triggered a large-scale aggregation of steel maggots on the P3 platform without their knowledge. They gathered near the exit because that was the direction in which the vibration transmission was most concentrated.

"Concrete curing agent," said Engineer Qin, pulling two bottles from the half-box of curing agent from her pocket. "Can we use them?"

Xie Chengzhou took the bottles and glanced at them: two bottles, each about 500 milliliters, acidic, which would dissolve and deactivate the shells of individual steel maggots within about ten seconds of contact. The two bottles could clean an area about one meter wide and one meter long outside the exit.

The coverage area outside the outlet is three meters.

"It's not enough," he said. "It can only clear a passage about one meter wide, but there are still passages on both sides. If you touch the sides while passing through, it will still trigger."

"Then hurry," Liu Feng said, "clear a path so everyone can run across."

"Run," Xie Chengzhou said, "on this platform, running will trigger a larger-scale gathering."

"We're already inside P3," Liu Feng said. "The area outside the exit is already like this. How many more people can gather here?"

Xie Chengzhou went through the logic in his mind and then admitted: Liu Feng was right.

"Okay," he said, "I'll clear a path with the maintenance agent first, then everyone can run."

He unscrewed the cap of the conditioner bottle and poured it into the area covered by steel maggots outside the outlet, starting from the center of the outlet and extending outwards to create a channel about one meter wide.

When the acidic liquid comes into contact with the steel maggot's shell, the reaction is immediate—the shells covered by the acid begin to dissolve, changing color from rusty red to grayish-white from the surface inwards, and then to the powdery state of corroded metal. They stop moving, stop responding, and within about ten seconds become a layer of inactive debris.

The passageway has been cleared, about one meter wide, extending from the exit to the concrete safety zone for about three meters.

"Run," Xie Chengzhou said. "Wu Ming, Engineer Qin, Old Chen, in that order."

Wu Ming ran away.

Qin Gong ran away.

Old Chen ran, his right hand clenched, his steps a little uneven as he ran, but he made it through, reached the concrete safety zone, and stood firm.

Then there's Liu Feng.

When Liu Feng reached the middle of the passage, the steel maggots on the right side of the passage began to move towards the inside of the passage at a faster speed than Liu Feng's running speed.

Liu Feng sensed it, so he sped up and ran forward. He reached the concrete safety zone, steadied himself, and then looked back towards Xie Chengzhou and Xu Kai.

The passageway had been re-covered by steel maggots, narrowing before their eyes and disappearing from their sight.

"We can't get through," Xu Kai said.

Xie Chengzhou quickly assessed the situation in his mind: the passage had been re-covered, the maintenance agent had run out, and the two people were inside the P3 exit. The density of steel maggots outside had exceeded the tolerance limit of any feasible route. The surge window was about two seconds, and it would take about one second to run three meters, which was theoretically feasible. However, the density of steel maggots on both sides of the passage meant that the vibrations during running would immediately trigger secondary aggregation, and the coverage speed would be faster than their running speed.

He kept the assessment results to himself and didn't say them aloud.

Just then, Liu Feng spoke up.

"I'll do it," he said.

The voice was flat, not a shout, but the kind of tone used to confirm something one last time before making a decision. He was already moving, walking from the concrete safety zone toward the entrance of the passage. He reached the entrance, stood there, put his feet firmly on the ground, and stretched out his arms.

"Liu Feng," Xie Chengzhou said, "No—"

"Quickly," Liu Feng said, "When the surge comes, you run. I'll hold it off here. I'll block the sides, and you run over here."

Xie Chengzhou mentally reviewed the plan: Liu Feng would stand at the entrance of the passage, using his body to physically block the steel maggots from moving from both sides into the passage. In the split second of the surge, Xie Chengzhou and Xu Kai might be able to run through.

possible.

"After you finish running, you run after me," Xie Chengzhou said.

"They can't escape," Liu Feng said. "They'll come as soon as I move, I know that." He paused for a moment. "Stop dawdling."

He was a construction worker who had been on construction sites for twenty years. He had done this kind of thing before—holding up a spot so others could go first. He knew what that meant. He went through the thought in his mind, then stretched out his hands and planted his feet firmly.

Xie Chengzhou looked at him without saying a word.

He knew Liu Feng was right.

The surge is coming.

"Run," Liu Feng said.

Xie Chengzhou ran away, Xu Kai ran away, they stepped onto the passage, took two steps, and reached the concrete safety zone, where they stood firm.

Xie Chengzhou glanced back.

Liu Feng was still standing at the entrance of the passage. On either side of him, the steel maggots had already passed by his hands, but he stretched out his hands to block them as much as he could. He stood there, his feet firmly planted, his hands outstretched. The steel maggots gathered around his hands, and the corrosive liquid began to spread from the point of contact, from his fingers to his palms and wrists. He did not move; he held that position firmly.

His palms were turning black.

The color under the skin changes as it spreads outward from the point of contact. It's not just on the surface; it's the kind of color that changes from the inside out after corrosive substances have seeped into the skin. It's deep, stable, and irreversible.

His fingers were trembling, not from fear, but from the stress response caused by the corrosion in his nerves, a subtle, involuntary trembling of muscles before they lost control.

He remained silent.

"Let's go," he said, his voice still flat, "Don't look anymore."

Xie Chengzhou looked away from him.

He walked towards the settlement area without stopping.

---

The five people left the concrete safety zone and headed towards the trestle bridge between P3 and P2: Wu Ming, Qin Gong, Lao Chen, Xu Kai, and Xie Chengzhou.

The subsidence nodes of the trestle bridge were more severely corroded than when they arrived. Xie Chengzhou glanced at them from the edge of the P3 platform and memorized the new vibration amplification ratio: it was about sixty percentage points higher than when they arrived, and it was already close to the structural critical value.

"The sinking point," he said, "is to increase the stride length, to leap over it without landing on that point, about twenty centimeters longer than when we came."

He left first.

As the surge came, he stepped onto the pier, walked, and felt the vibration distribution under his feet. When he reached the sinking point, he took a step, landed firmly, and continued walking until he reached the P2 platform and stood firm.

Then came Wu Ming, then Qin Gong, and then Lao Chen.

When Lao Chen reached the sinking node, Xie Chengzhou was watching him from the P2 platform.

Old Chen's right hand was clenched, and the three cuts would bleed when he clenched his fist. His arm swing was limited because his right hand was clenched, and the limited arm swing affected his stride length. His stride length was about 20 centimeters shorter than usual. He knew this, and he could feel it when he walked. He tried to compensate by rotating his hip joint to make up for the lack of arm swing.

He walked to the sinking point and took a step.

Insufficient step length.

It wasn't a huge difference, but about twelve centimeters. His foot landed on the edge of the sinking node, not directly above it, but on the edge. The vibration amplification was lower than that directly above the node, but higher than the safe zone.

A buzzing sound appeared.

It's not coming from either side of the pier, but from below, from below the sinking node, below the waterline, where the steel maggots have been activated for a longer time, and they are moving upwards.

"Old Chen, head towards P2," Xie Chengzhou said. "Don't stop, keep going—"

Old Chen took a step forward, and then the steel plate beneath his feet made that sound.

A low, short, metallic sound of internal collapse.

It wasn't a single piece broken; it started tearing from the corroded edge, beginning at the edge where Old Chen's foot was, and extending outwards. The tearing was faster than he was walking forward. His right foot stepped into the tear, his ankle sank, and he fell to the side, his right hand instinctively grabbing at the steel handrail.

He caught it.

His right hand, the one with the three cuts, gripped the steel handrail. He was suspended there, his feet dangling in the air. The P2 platform was about two meters in front of him. Xie Chengzhou was at the edge of the P2 platform, and he could see Old Chen's face.

Old Chen is watching him.

It wasn't a cry for help, nor was it fear; it was the expression of someone who had calculated a plan and then confirmed that it was unfeasible. Xie Chengzhou recognized this expression; he had seen it on construction sites and on the workers who had made the decision.

Xie Chengzhou took a step forward, "Old Chen—"

Old Chen lowered his head and glanced at the hand that was gripping the steel pipe.

Three cuts, the blood had already congealed, but there were steel maggots on the steel pipe, and the corrosive liquid began to spread from the point of contact. His fingers were trembling, not from fear, but from the stress response to the corrosion. His grip strength gradually decreased with that trembling, and he could feel it.

He glanced in Xie Chengzhou's direction, then lowered his head.

He let go.

It wasn't corrosion that made him loose; he loosened up on his own.

Xie Chengzhou was at the edge of the P2 platform. He saw the action of letting go, and he saw Lao Chen bow his head before letting go—that bow was not giving up, but the kind of action that comes from someone who has worked on construction sites for thirty years, after going through all the numbers, accepting the conclusion.

The sound of Old Chen falling into the sea was drowned out by the surging waves.

Then the surge receded.

Xie Chengzhou stood at the edge of the P2 platform for about three seconds.

He went through Old Chen's name in his mind.

Then he looked away from that direction and towards Xu Kai. "Come here," he said, "jump from this end."

Xu Kai jumped over; he arrived at the P2 platform and gained a foothold.

Four people, P2 platform: Wu Ming, Qin Gong, Xu Kai, Xie Chengzhou.

Xie Chengzhou didn't count, but he knew there were four.

---

They used the temporary passage from P2 to P1.

Wooden planks were laid on the crane boom, extending from P2 to P1. Xie Chengzhou walked up to them and checked them out: intact, undamaged, and the vibration isolation effect was still working.

They walked past them one by one.

When Xie Chengzhou reached P1, he glanced at the concrete area.

Fang Yuan is no longer there.

At the edge of the concrete area, next to the crane base, where he had sat, there was only a slight indentation, the kind of mark left on the concrete surface after someone sat on it. It was shallow and inconspicuous, but Xie Chengzhou saw it.

He squatted down next to the indentation and stared at the spot for about three seconds.

The shape of the indentation is that of a person sitting, not standing or lying down, but sitting with their back against the crane base and their feet flat on the ground, not bent—the same posture as when Fang Yuan left.

However, there is a shallow scratch next to the indentation, extending about 20 centimeters from the edge of the concrete area toward the steel plate. It is the mark of something being dragged over, or the heel left on the concrete surface when someone moved toward the steel plate.

Xie Chengzhou went through this in his mind.

Fang Yuan's right foot was burning, making it impossible to precisely control his landing point. The longer he waited in the concrete area, the more the burning sensation in his right foot spread upwards, reaching his calf, his knee, and ultimately, his entire leg's control. Xie Chengzhou didn't know how long he waited, but the scratch was pointing towards the steel plate, not towards the passageway.

He wasn't trying to get through the passage.

He was moving in another direction.

Xie Chengzhou went through this deduction in his mind, then suppressed it and didn't continue thinking about it.

He stood up without saying a word.

The surge came, then receded.

He looked away from the indentation.

---

The evacuation signal is not a sound, but a feeling.

Xie Chengzhou stood on the concrete area of ​​the P1 platform and felt it: a slight, even pressure rising from the soles of his feet. It wasn't a vibration, but a feeling of being steadily caught by something, mirroring the "sinking" he experienced when he first entered the realm.

My vision started to turn white.

It wasn't a blinding white, but rather a process where the color faded from the edges. The sea turned white first, then the sky, then the outline of P3, then P2, then the pier, then the concrete beneath his feet, and then everything turned white.

He checked his body's condition in the white light: both hands, ten fingers, salt stains on his coat, and a shallow scratch on the back of his right hand, from the edge of a wooden beam when he ran past the P3 exit; it wasn't deep and had already scabbed over.

His hands were steady.

The white is shrinking, folding and disappearing from the edges towards the center.

He was in Yuan City.

He paused for a moment, waiting for his vision to stabilize, before turning his gaze to the side.

Wu Ming was on his left, Qin Gong was on his right, and Xu Kai was about three steps in front of him.

Four people.

Xie Chengzhou mentally reviewed the number.

Twelve went in, and four came out.

He suppressed that number, not elaborating on it here, not because he didn't know what it meant, but because he knew that elaborating on it here would be pointless.

He looked at the inside of his wrist, rolled up his sleeve, and glanced at the text below the number: "Trials - Isolated Island Construction Site - Completed. Score Calculation in progress."

Then he rolled up his sleeves and walked toward the checkout area.