The heavy door to Lab 7 latched behind me with a solid metal click. Luke was already there. He was leaning over the primary mount, sleeves shoved up his forearms, a coil of thick black cable resting against his hip. "Morning, Mercer," he said without looking up, carefully working a zip-tie free with a pair of snips. "Thought I’d beat the rush." "My alarm went off early," I said, setting my bag down by my workstation and waking the dual monitors. "Did you sleep here?" He straightened, holding up a pristine sensor cable with fresh connectors. The dimple showed at the corner of his mouth. "Behold: brand new from the storage cage. I got there before everyone else could loot the place." "Impressive. My sister commandeered my sofa last night, so coming in early was basically self-defense." "That sounds ominous." "She brought textbooks. It was worse." Luke chuckled, setting the coil on the cart beside me. "Ready to tear it down?" "Ready." We spent the next ten minutes working in quiet coordination. Luke navigated the tight clearances around the motor housing, unclipping the original line while I tracked the port assignments on screen. When he handed me the discarded cable, his fingers brushed against mine—warm, slightly rough, and leaving a quick, grounded prickle of awareness behind before we moved to the next step. He threaded the replacement line through the clips and snapped it into the primary port with a solid click. "New cable seated," he announced, wiping his hands on a clean rag. "Let's see if the easy suspect gives up." I brought the monitoring tools back online. Green checkmarks populated down my left-hand monitor in a tidy column. "System is clear," I told him, fingers hovering over the keyboard. "Let's check the baseline first." Luke stepped to the manual safety switch. "Starting the motor." The drive started with a steady, smooth whir. On my screen, the line stayed completely flat and blue right down the center. We watched it run for three minutes. Nothing. "Quiet," Luke said, watching the steel shaft turn. "Right. Now let's try the load." Yesterday’s discovery was clear in my head: the alarm only tripped when the machine was working hard. "Take it up to full power, but keep it steady." "Spinning up to maximum," Luke said, adjusting the controls. The motor pitch rose to a harsh, mechanical whine. We held our breath, watching the numbers scroll. Ten seconds. Twenty seconds. A full minute. The graph stayed flat. I blew out a slow breath. "Still nothing. It's not doing it." Luke frowned, resting his hand flat on the steel housing. "Still dead calm. But yesterday rapid cycling tripped the alarm immediately." "Yesterday we were slamming it with stop-and-start cycles at the same time," I said, looking from yesterday's saved logs back to today's flat blue line. "We tested the load and the cycling together. We never separated them." "Right," Luke said, leaning in toward the display. His shoulder came down near mine as he pointed at the graph. "So running hard isn't what trips it. What if it's the sudden jump? Going from idle straight to maximum in half a second?" "Not the work," I murmured, seeing it click into place. "The kick." "Let's kick it." "Setting parameters," I said, fingers moving across the keys. "Five seconds at idle, then an immediate jump to full power." "Ready." I hit the return key. The machine sat quiet for five seconds, the motor ticking over at a low idle. Then the controller commanded full power in a single burst. The motor surged. Luke kept one large hand planted flat against the casing. At that exact instant, a sharp red spike shot straight through the top of my graph before dropping back to normal. "Anything?" I asked quickly. Luke shook his head. "Just the normal pull when the motor kicked in. No vibration." "Look at the screen," I said, pointing with the tip of my pen. "Right when the load changed. It tripped the limit for half a second and went right back to sleep." "Do it again," Luke said, his voice dropping into that quiet, absolute focus. I reset the sequence and fired it. Five seconds idle. Sudden jump. Bam. The exact same red spike stabbed the top threshold, vanishing the moment the motor settled into a steady hum. Luke grinned, hazel eyes bright. "We have it. It’s not running hard that breaks it, Mercer. It's the jump." "The sudden change in load," I agreed, a laugh of pure relief slipping out. "That’s our trigger." A shadow crossed the threshold. Dana Kim was standing in the doorway with a tablet tucked under one arm, her sharp gaze sweeping from our faces to the monitors. "We narrowed it down," Luke told her, leaning back against the bench with an easy shrug. "Ruled out the cable. The false reading only happens during a sudden jump to full power." Dana stepped into the lab, looking over my shoulder at the twin spikes on the screen. "So it isn't happening while the machine stays at full power," she said. "It's happening when it gets there?" "Exactly," I confirmed. "Can you filter it out in software?" "Not safely," I answered. "If something actually breaks during startup, the system still needs to catch it. We have to know where this signal is coming from before we teach the software to ignore anything." "Fair enough," Dana said, tapping the corner of her tablet. "Keep digging. Just remember: twelve weeks sounds generous until leadership starts showing up in safety glasses. Make sure this thing is ready when they do." "On it," Luke said. Dana gave us a crisp nod and turned on her heel, leaving the lab as quietly as she'd entered. The room went quiet again, leaving just the soft drone of the overhead lights and the cooling motor. I pushed back my chair, walked over to the large whiteboard hanging on the wall, and grabbed a dry-erase marker. I wiped away yesterday’s scribbled notes, uncapped the pen, and wrote: WE KNOW: 1. The frame isn't actually shaking. 2. New cable, same reading. 3. It happens during a sudden jump to full load. I capped the marker with a sharp snap and looked over my shoulder. Luke was watching from the console, one eyebrow quirked, that familiar, patient smile tugging at his mouth. "Step four," he said quietly, "is figuring out why the hell it cares."

Chapter 5: Transition States