Harbor Unit’s lower service chamber breathes cold through the concrete. The monitor glows with Dallas’s trace, a personnel entry locked in red, and the relay keeps clicking beneath the floor like a nervous finger on a trigger.

Jackson holds the doorway with his shoulders square, but his eyes stay on the monitor. The name on the highlighted entry matches a Harbor Unit internal handler, and the line under it points straight back to the service spine beneath the monument.

A maintenance hatch shudders open in the floor, and a wet draft rolls up from below. Something moves in the dark below the grate, slow and heavy, as if the tunnel itself is waking up.

Dallas snatches the personnel log from the monitor stand, and the red highlight flickers across his glove. The clicking below the floor speeds up.

Jackson steps away from the doorway to make room, but he keeps his body angled toward the hall, ready for company.

The Figure leans toward the open hatch, then glances back at Dallas as the floor gives another wet shudder.

Dallas drops into the hatch with the log tucked tight against his chest. The steel ladder bites cold through his shoes, and the chamber above falls away as he descends into the dark.