Brell agreed to the test after she changed the escape route.
“The door is too narrow for six people carrying tools,” she said. “Two observers inside. The rest stay at the junction.”
Sera pointed to the mounting on Neri’s drawing. “I need to see the damaged edge.”
“And I need my crew to come out if the whistle sounds.”
Iven stood between them at the worktable outside the chamber. “Two inside at a time. We change places after the plate is installed.”
Brell considered him. “You and Dessa do the plate. Kesh watches the opening from the door. Sera gets her look after you come out.”
Neri had designed the removable cover and wanted to inspect it, but she accepted the limit. She could see the plate through the doorway once it was in place. Elian would keep time at the junction, where he could hear Brell’s whistle and see who entered and left.
The shift engineer had arranged a reduced flow for the whole morning. She had also put a lock on the upper valve and given Brell one of the keys. It was a small piece of authority, made of brass and no longer than Iven’s thumb. Brell wore it on a cord around her neck.
“If someone wants the flow restored,” she said, “they can find me.”
Kesh looked through the door’s viewing panel. “Empty.”
“Empty where you can see,” Iven said.
“Yes.”
They had added a second panel near the hinge by removing a loose inspection plug. It gave them a view of the low opening beneath the pipe. Neither panel showed the upper seam completely. The crew had placed a shallow tray of pale dust below the seam, where falling grains might reveal movement. It was not a trap. It was another way to notice what their eyes could not see.
Iven checked his tools. The replacement plate sat on a cart with the removable cover beside it. Dessa had brought a second maintenance jack, since the first remained in the chamber. Neri had marked the safe attachment points in red paint on the plate’s drawing. There were only two. If either proved unsound, they would stop and redesign.
Brell lifted the bolt. Kesh opened the door and held her shield across the lower gap while Iven looked inside. The first plate still hung from its upper fastener. The jack stood beneath the pipe, slightly tilted. The lower bracket lay beside the mounting, marked by pale scratches.
Nothing moved at the opening.
Iven and Dessa entered. Kesh remained at the door. Brell watched from behind her with the whistle ready.
“Jack first,” Iven said.
Dessa set the replacement jack beneath the pipe, a little farther from the wall than the first. Iven raised it until it took the pipe’s weight. The old jack could then be lowered and moved clear. Its base had bent where the larger creature struck it, but it was still usable after repair.
They removed the partly installed plate. Iven checked the upper fastener and found the frame sound. The lower attachment point was less convenient: a rivet head stood proud of the metal, leaving the new bracket unable to sit flat.
“We stop?” Dessa asked.
“Let me see.”
He measured the gap with his folding gauge. The rivet itself was solid. The bracket could be notched without touching the wall, provided the notch did not weaken the bolt hole. He showed Dessa the measurement.
She called the numbers to Neri, who repeated them back. There was a pause while Neri considered.
“Notch the bracket,” she said. “Keep the edge round. No sharp corner.”
Dessa took the bracket out to the junction, where Jem had set up a small file and a vise. Iven remained in the chamber with Kesh watching. He did not touch the damaged surface. He used the time to inspect the pipe’s movement and mark a line where the plate could stand clear of it.
The dust tray beneath the upper seam remained undisturbed. The low opening stayed dark.
Dessa returned with the notched bracket. Iven fitted it against the frame. It sat flat. Together they lifted the plate, guided it around the pipe, and secured the upper fastener. The lower bracket took longer. The bolt threads had a burr that caught after the second turn. Iven removed it, cleaned the thread with a small file, and tried again.
The bolt went in smoothly.
“Test the load,” Neri called.
Iven lowered the jack a fraction. The pipe settled against the new supports. It moved with the reduced flow but did not strike the damaged wall. The plate carried the load to the frame on either side.
“Again,” Neri said.
He lowered the jack another fraction. The supports held.
Dessa touched the plate lightly. “No knock.”
“Not one we can hear,” Iven corrected. He placed a small metal washer on the upper edge. It trembled with the pipe but did not jump.
They removed the jack and backed out. Kesh closed the door behind them. Brell marked the time on Elian’s sheet.
Sera entered with Kesh after the others had cleared the junction. She carried a lamp and a narrow sample tool. Iven watched through the upper panel while Neri watched through the lower one.
Sera approached the damaged mounting from the side. She did not remove the plate. The small opening Neri had left exposed a narrow section of the darkened surface, enough to see the tear without reaching behind the pipe.
Sera touched the edge with her probe and drew a small sample into the tube. Kesh stood near the door, looking between the low opening and the upper seam. No creature appeared.
Sera returned to the junction and sealed the tube. “The surface is living,” she said. “It’s damaged. I can’t tell from this alone whether the creature was making the damage or responding to it.”
“What about the strand at the wash platform?” Elian asked.
“I need to compare it under the lens. It may be a deposit from the creature. It may be material produced by the tissue itself.”
Brell looked at the time. “We have one hour before the engineer wants an update.”
They observed the chamber with the opening uncovered. The pipe moved under reduced flow. The damaged tissue remained exposed through the gap in the plate. After twelve minutes, pale dust fell into the tray beneath the upper seam.
Kesh held up a hand. A creature appeared at the seam, its head low. It descended halfway down the wall and stopped. Its armor was smaller than the one Iven had struck the day before, though it could have been a different individual altogether.
The creature approached the mounting. It touched the edge of the opening, then moved away from the pipe and disappeared through the low passage.
Elian recorded the time and what each observer had actually seen. He did not write that the creature had inspected the wound. Kesh had used that phrase once; Sera had crossed it out in favor of touched the edge. The difference mattered.
They waited another interval. No creature emerged.
“Cover,” Brell said.
Iven and Dessa entered again. This time the cover went onto the outside of the plate. It was a shallow metal hood with open space beneath, attached to the frame rather than the tissue. The work took less than a minute. They withdrew before the creature returned.
The second observation was quieter. The pipe continued at the same reduced setting. The cover hid the damaged edge from the chamber but did not seal the entire wall. Elian watched the time. Kesh watched the openings. Iven watched the washer on the support plate.
After fifteen minutes, the upper seam remained still. After twenty, the low opening produced a faint scraping sound, but nothing came out. At twenty-four minutes, Brell ended the observation.
“We’re not staying until something bites us just to get a longer number,” she said.
Elian wrote down the interval. “One creature came out during the uncovered observation. None came out while the cover was in place.”
“Today,” Kesh said.
“Today,” he agreed.
Sera looked at the data. “It suggests access to the damaged edge may matter. It doesn’t tell us whether the cover prevents the creature from reaching it through another passage.”
“And it doesn’t tell us what happens at full flow,” Neri added.
Brell rubbed her thumb over the brass key. “But the mounting’s secure.”
“As far as we can test under reduced flow,” Iven said. “Before the engineer restores it, we should increase pressure in stages.”
“That was my next sentence.”
“Then I apologize for stealing it.”
“You can pay me back by carrying the jack.”
He did. The old jack was heavier than it looked and less cooperative after its base had bent. Iven and Dessa carried it to the cart, where Jem secured it beside the tools. Neri sent him back to the workshop with instructions not to repair the base until he had checked the screw for a hidden bend.
The shift engineer arrived with the woman in the blue apron. The engineer introduced herself as Vela and inspected the plate, the cover, and the written observations. She had a narrow face and a habit of reading the last line of a page first.
“You’ve reduced the pipe movement,” she said.
“We’ve redirected it into the frame,” Neri replied. “At this setting.”
Vela looked at Brell. “I’ll raise the flow one step. If the plate moves beyond this mark, you signal me and I close the valve.”
She pointed to the line Iven had drawn on the support. Brell agreed. The woman in the blue apron went to the upper valve room with a signal lamp. Another worker stood at the local shutoff wheel.
The first increase changed the pipe’s sound from a soft pulse to a low hum. The washer on the support trembled more quickly. The plate moved toward the mark and stopped short of it.
They held the setting for several minutes. No creature emerged. Sera watched the drain beneath the cover. A small drop of dark fluid fell into the tray they had placed below it, then another. The cover had not sealed the tear.
Vela made a note. “One more step?”
Neri checked the fasteners. “One.”
The second increase brought the pipe closer to its ordinary rhythm. The plate held. The washer vibrated but remained in place. Through the lower viewing panel, Kesh saw movement in the opening: a pale foot gripping the edge, then withdrawing.
Brell raised the whistle but did not blow. Everyone remained still.
The foot appeared again. A head followed. The creature looked toward the covered mounting, then crossed the chamber toward the drill stand still lying on its side. It struck the stand once, producing a loud metallic ring.
Iven flinched despite himself. The creature struck it again. It did not approach the door.
“Existing creature,” Kesh said quietly. “Still active.”
“Still dangerous,” Brell replied.
Vela lowered the flow one step. The pipe’s hum softened. The creature remained beside the stand.
They could have stopped there. They had a secure support, an observation that the cover changed the number of creatures emerging during a limited interval, and a clear demonstration that one creature stayed active despite the cover. Sera wanted a longer comparison; Kesh wanted to know where the creature went next; Brell wanted her crew out before the heat cycle changed again.
Brell won.
She closed the chamber door and handed Vela the written measurements. The engineer agreed to keep the flow below the final setting until the next inspection. The terrace kitchens would need a second stored-heat cycle, and the valve room would complain. Vela said she would deal with the complaint.
“Why?” Iven asked her as they climbed the stair.
“Because I signed the first reduction,” she said. “If the pipe fails after I restore it too quickly, my name is on the instruction.”
It was not the only reason a person might protect a crew. It was a reason she could use in a room full of supervisors.
Outside, the afternoon light had shifted across the deck. Neri sat on the cart edge and drank water from a dented flask. Dessa leaned against the rail, looking more tired than she had during the fight in the chamber.
“We did it,” Dessa said.
“We installed a plate,” Neri replied.
“And didn’t get bitten.”
“That part I count as success.”
Sera carried her sample case carefully. “I’ll compare the tissue with Kesh’s material from the wash platform. Don’t let anyone say we’ve proved the creatures are harmless.”
“I don’t think anyone who saw them would,” Brell said.
Elian held up the observation sheet. “Can I copy this for the survey office?”
Kesh hesitated. “Copy it exactly. Include the times and the things we couldn’t see.”
“I will.”
Iven looked back toward the stair. The chamber remained occupied by a creature strong enough to tear metal. The pipe still needed a full-pressure test, and the damaged wall still needed treatment. None of that had been solved by a single observation.
They had, however, made the next decision with more information than the last. He had learned to value that, even when the information refused to fit on a clean line.