The first old sacrificial channel ran behind the central return panel. Gu opened the panel and stopped when he saw the copper strip. Its contact joined a local barrier to a compulsory population feed. The local light remained on, but the drawing showed the command line tied to the same strip.
“I signed off on this layout,” Gu said. “We copied the pattern from the old Registry designs. It made the distribution simple.”
Qiao Wen checked the field panel before touching anything. “The local circuit is working. I’ll bypass the command contact and test the barrier before you isolate the strip.”
Qinghe kept the central pressure steady while Qiao opened the bypass. The light held. He tested the local release twice, opening and closing the valve under the field reading. It responded to the station controls alone.
Qiao did not close the panel after the first test. He compared the field meter with the central reading and waited for both needles to settle. Then he opened the local valve again while Gu watched the population feed. The barrier light held on its own circuit. When Qiao closed the valve, the local mark changed; the central compulsory line did not.
Gu looked at the copper strip he had designed. “If we had separated the contacts at the start, the command could not have taken the household feed.”
