Sera asked Iven to close the clinic door before she showed him the drawing.
It was a cross-section of a regulator, carefully inked on paper that had yellowed along the folds. Two chambers connected through a narrow valve. A set of marks beside the valve showed pressure at different intervals. Iven recognized the general shape from equipment in Mercy’s lower passages, though this version was smaller and built for precise adjustment rather than bulk flow.
“I drew that fifteen years ago,” Sera said.
He looked at the signature in the corner. S. Holt, written in a firm hand. “For the College?”
“For a surgical team. They were treating injuries in the internal tissue. The old regulator delivered pulses too sharply. I designed a valve that spread the pressure over a longer interval.”
“Why?”
“Because the people operating the instrument believed the tissue response was pain.” She sat opposite him. “I believed it too.”
Iven looked again at the marks. The improved valve would reduce the peak pressure while maintaining the total delivery. It was a sensible alteration if the goal was to prevent a violent reaction during surgery.
“Did it work?”
“In the first tests, yes. The tissue contracted less abruptly. Workers could operate without the whole chamber moving around them. Several injuries were treated successfully.”
“That sounds useful.”
“It was.” She folded her hands. “The same valve was later fitted to a larger regulator. My supervisors found that a sustained pattern could reduce other responses as well. Not just the reaction to a cut.”
“What other responses?”
“Changes in circulation. Coordinated contractions. Some reactions to sound and movement.”
“You knew?”
“Not at first. The larger system was outside my assignment. When I saw the records, I asked what it was doing. I was told the responses were involuntary and that reducing them protected the city.”
“Did you believe them?”
“For longer than I should have.”
The clinic was quiet except for a kettle beginning to move on the stove. Derrit had gone home the previous day with a splint and a list of instructions. Sera’s assistant was delivering medicines. For once, nobody was waiting outside the door with a wound or a question.
Iven traced the line from the valve to the second chamber. “Did you know the system before yours existed?”
“Yes. I didn’t invent the first regulators. They were already old. I improved one current model.”
“And they used your improvement to make it do more.”
“Yes.”
“Did you stop them?”
“I tried after I understood. I asked for the test records and challenged the interpretation. I was told I had exceeded my authority. Then I was told my work could no longer be trusted.”
“That’s a convenient order.”
“It’s also true that I had failed to follow my own work far enough.” She looked at the drawing rather than at him. “I knew the regulator had been adopted elsewhere. I accepted that the people using it had better information. I wanted that to be true.”
Iven thought of the old pump reading he had signed, and kept his face still. Sera was telling him about her work. She had not asked him to turn it into a measure of his own.
“Why tell me now?”
“Because we’re looking at the same system. If I ask you to help me examine it, you need to know what I contributed. And because Elian’s office may find my name before I put it in front of you.”
“What were you treating?” he asked.
“A tear near a circulation chamber. The crew had found it during a routine inspection, and every time they tried to close it the surrounding tissue tightened. One man lost two fingers when a clamp shifted. Another was struck by the tool he was holding. I was asked to make the operation safer.”
“Did the tear close?”
“Yes. The second team sealed it after the new valve was fitted. I watched the pressure settle and thought we had made a good thing.” She paused. “We had, in that room, on that day.”
“Who was the technician?”
“Vessa Fenn. She measured the responses. She argued that the contractions were organized, not random, and she wanted a longer observation before we altered anything. I told her the workers couldn’t wait while we studied every movement.”
“Could they?”
“Perhaps not. The tear was getting worse. But that was a reason to treat it carefully, not a reason to stop asking what the movements meant.”
Iven looked at the inked valve. The drawing showed no blood, no frightened workers, no chamber tightening around a tool. A person could study it for years and never know why it had been made.
“Is Fenn the technician you mentioned?” he asked.
“Yes. She left the College before I did. Last I heard she was working at a water-testing station.”
“Would she remember what she said?”
“Vessa remembers arguments the way other people remember birthdays.” Sera’s mouth moved. “She would be offended if I asked that.”
“Then ask her something else first.”
“I intend to. Whether she’ll open the door is another question.”
He turned the drawing over. The reverse held a list of materials and a sketch of a smaller spring. The handwriting changed halfway down the page.
“Whose is that?”
“Vessa’s. She noticed the spring would wear unevenly and made me alter it.”
“Did you thank her?”
“I bought her a very bad meal.”
“Was that gratitude?”
“It was the only meal we could afford near the laboratory.”
He picked up the drawing. “Do you still have the tests?”
“Some. Not all. I copied what I could before I left.”
“Can I see them?”
“That’s why I brought you here.”
She took a second packet from her case. The pages inside recorded pressure, timing, tissue response, and observations made by three different technicians. Several lines had been crossed out and rewritten. One entry described a sustained contraction that stopped when the regulator was disconnected. Another noted that the tissue did not respond to a repeated impact while the device was operating, but did respond afterward.
“Was the impact the same each time?” Iven asked.
“The technician says it was. I can’t prove she applied it with exactly the same force.”
“Could the tissue have been tired?”
“Yes. Could the equipment have changed the response? Also yes.”
“Did anyone repeat it?”
“Twice. The second result was less clear. The third was removed from the copy I received.”
“Removed by whom?”
“I don’t know.”
He turned the page toward the lamp. The edge showed a narrow strip where paper had been cut away. “You could have done that yourself.”
“I could have.”
“I don’t think you did.”
“Don’t decide that because you like me.”
“I haven’t decided whether I like you.”
“That makes two of us.”
He smiled despite himself. Then he looked at the drawing again. “If the valve reduced a response, it could still have been used to make surgery safer.”
“Yes.”
“And it could also have been used to keep something from responding when it should.”
“Yes.”
“We need to see the larger regulator.”
“We do. But not by breaking it. If it controls circulation as well as response, a sudden interruption could harm the people above and the tissue below.”
“That sounds like something you learned the hard way.”
“It is.” She rose to take the kettle off the stove. “I once disconnected a smaller unit to prove what it was doing. A pressure line failed. Two workers were injured.”
“Were they told why?”
“I told them. I also told the supervisor, who wrote the incident as a maintenance error. I did not insist on correcting the record until later.”
She poured tea. The smell was strong enough that Iven suspected the leaves had been left in the pot since the previous evening.
“You could have told me this earlier,” he said.
“I could have. I was afraid you’d decide I was trying to hide it.”
“Were you?”
“Yes. For a while. Then I was afraid you’d be right.”
He accepted the cup. The tea tasted as strong as it smelled. He drank it anyway, because she had made it and because putting it down immediately would have turned the conversation into a problem about tea.
A knock came at the door. Neri entered with a roll of support drawings. She stopped when she saw the papers on the table.
“Am I interrupting?”
“Sera’s telling me about a regulator she designed,” Iven said.
Sera looked at him, then at Neri. “You should hear it too.”
She gave the account again, more briefly. Neri listened without interrupting. When Sera finished, Neri unrolled the support drawing beside the old cross-section.
“The version near the passage has a similar valve,” she said. “I saw the housing when we checked the drill damage.”
“Did you see a maker’s mark?” Sera asked.
“No. The housing was covered.”
“We can look when your crew installs the supports.”
“If the guards allow it.”
“We can ask the engineer to include it in the inspection,” Iven said.
Neri nodded. “That gets the housing opened for a reason they understand.”
“Will the device still be operating?” Sera asked.
“Probably. We won’t touch the pressure line unless the engineer agrees to isolate it.”
Sera looked at the two drawings. “I don’t want my history to become an excuse for someone to damage the system in haste.”
“And I don’t want it to become an excuse for leaving it alone,” Iven said.
“Neither do I.”
The clinic door opened again. Elian entered with a leather folder under his arm. He had spent the day in the forward storage room and looked as though the dust had followed him home. He set the folder on the table and noticed the regulator drawing.
“What’s this?”
Sera told him. His first question was whether his father had known about the later use. His second was whether Sera could prove that the response had been suppressed rather than simply altered by injury.
“I can’t prove either yet,” she said.
Elian accepted that more readily than Iven expected. “The older maps show a service route through the area where the rooms are. The later map marks it as solid support. The change was signed by a surveyor who died before my father took office.”
“Did the surveyor explain why?” Neri asked.
“The note says the route was closed after instability. It doesn’t mention the rooms.”
“Could the surveyor have missed them?”
“Possibly. The note refers to a collapse near the old door. The room may already have been sealed.”
Iven looked at Sera’s pages. Every answer seemed to reveal another place where a person had made a decision with only part of the evidence. That did not make the decisions harmless. It made finding the truth more work than choosing a villain and stopping there.
Elian opened the folder. “I copied the route. There’s a junction beside the regulator housing. If the engineer approves the support work, I can compare the current passage with this plan.”
Sera handed him the test record. “Read this first. If you quote it, include the uncertain result.”
He did. Neri rolled her support drawing tighter. Outside, the slow shift of Mercy’s gait passed through the clinic floor. The cups rattled together on the shelf and settled.
Iven watched Sera gather the old pages. “Are there people who remember the original tests?”
“One technician might. I don’t know whether she’ll speak to me.”
“Will you ask?”
“Yes.”
“Then ask her what she saw, not what she thinks you want her to say.”
Sera looked up. “That’s good advice.”
“I get it occasionally.”
She tied the packet closed. “Iven, I don’t expect you to forgive what I did.”
“I’m not sure what that would mean. I wasn’t one of the workers you injured.”
“No.”
“But I can help you find out what the regulator is doing now.”
Her shoulders lowered slightly. It was not absolution. It was a decision about the next piece of work, and for the moment it was enough.