Third overnight this week. Almost six hours at the console, mile and a half of laps around the building and the park nearby. The routine settles in by now — you know which vending machine still has Dr Pepper, which hallway is coldest, which bench outside has the best view of nothing.

Troubleshooting networks at 2 AM has a rhythm to it. Sit, diagnose, escalate, wait. Walk while you wait. Come back, check the ticket. Walk again. The walking is the thinking. The desk is just where you type what you figured out on the walk.