The air in Lab 7 was cool and quiet when I pushed the heavy door open on Thursday morning. Luke was already at his bench, leaning over a diagram with a travel mug and a paper bag from the bakery down the street. "Morning, Mercer," he said without looking up, tapping the edge of a plastic ruler against the paper. "Surprised to see you before eight-thirty after a four-round trivia marathon." "I am a creature of habit, Hayes," I said, setting my bag by the console and waking the dual monitors. "I have an unexplained spike waiting for me, Hayes. Fatigue can wait." He looked up, hazel eyes crinkling. "Fair enough. Ready to stare at the signal until it confesses?" "Always." I pulled up yesterday’s captured waveform—the sharp, cliff-like peak that appeared the instant the motor jumped into full power. Luke rolled his chair across the concrete until his armrest was inches from mine, completely unbothered by the shared territory. "Okay. We know it happens on the jump. We know the mechanical frame isn't physically trembling. And we know the spike doesn't follow the shape of the motor's actual torque curve." "Which means whatever is creating this signal, it's not just an exaggerated echo of the drive kicking on," I said. "What if it's not mechanical at all? What if noise is coupling into the sensor line upstream?" "We can check the auxiliary channels," Luke suggested, pointing at the secondary log menus. "Pull up the system-wide power monitoring logs from yesterday's runs. Look for anything that spikes at the exact microsecond the jump occurs." My fingers moved across the keys, aligning the timestamps. Hundredths of a second scrolled by in dense columns of voltage data. Then I saw it. "Wait," I said, leaning closer to the glass. "Channel Four. The auxiliary power supply for the control board." Luke leaned in beside me, his eyes tracking where I tapped the screen. Right at the bottom of the power graph, almost lost in the baseline noise, was a tiny, jagged hiccup. "Overlay them," he said quietly. I dragged the two traces onto the same axis. The vibration spike was a massive red cliff. Beneath it, the power blip was a microscopic tremor—but the leading and trailing edges locked together in perfect alignment. Luke let out a low whistle. "Well, look at that." "It's the exact same fingerprint," I said. "It's scaled down to almost nothing on the power rail, but the timing is identical to the microsecond. The fault isn't isolated to the vibration sensor." "It's hitting both," Luke said, leaning back with a slow nod. "Which means it’s either bleeding into both lines from a shared connection, or something upstream is kicking both systems at once." "Ground bounce was the obvious first suspect," I muttered, already pulling up the wiring schematic. "A rapid current draw somewhere on the board pulling the ground plane out of level." We spent the next forty minutes testing the theory. Luke re-routed the auxiliary board's grounding path to an isolated reference point while I re-initialized the telemetry filters. When the mount was ready, I hit the jump test. Idle. Five seconds. Sudden surge. Bam. The massive red spike flared across the vibration channel, and the identical tiny blip appeared right on schedule on the power rail. Luke stared at the monitor for three seconds. "Well," he said. "That was a beautiful theory." "It had a good life." "Twenty-seven minutes." "Some lives are shorter than others." The lab door swung open with a quiet clack. Dana stood in the doorway, a tablet tucked under her arm, dark eyes sweeping between our chairs and the display. "Tell me you have something I can repeat upstairs without lying," she said. "We can reproduce it on command," I answered. "We know it only happens during a sudden jump to full load, the signal has the exact same fingerprint every time, and we just confirmed that a microscopic version of it shows up on the control board's power rail." Dana paused, waiting. "And?" "We still don't know what's causing it." "There it is." "You asked for something you could repeat without lying." Luke leaned back against the workbench, hands tucked loosely into his pockets. "She takes requirements very seriously, Dana." Dana looked between the two of us, her expression utterly unreadable. "Find me a better sentence by Monday." "Working on it," Luke said. Dana gave a single nod and let the door swing shut behind her. The lab went quiet again. I pushed back my chair, walked over to the whiteboard, and picked up the dry-erase marker. Beneath the notes from yesterday, I added: 5. SAME FINGERPRINT APPEARS ON AUX POWER RAIL. 6. NOT A SIMPLE GROUND LOOP. I capped the pen and turned around. Luke was standing right beside me, one hand outstretched. "What?" I asked. "Marker." "Why?" "Operational requirement." "That isn't an answer," I said, but I placed the dry-erase marker into his palm anyway. Luke didn't touch the engineering notes. He stepped around me to the list, uncapped the pen, and below 4. CLAIRE REQUIRES FEEDING, he wrote in his lopsided, bold block letters: 7. MERCER IS ON THE TRIVIA ROSTER. I looked at the scrawl. He capped the marker with a sharp snap and handed it back, that slow, effortless grin spreading across his face. "Documentation matters," he said. "Apparently." I turned back to the console, dropped the marker into the plastic tray, and left all seven lines exactly where they were.

Chapter 9: Boundary Conditions