They passed a cracked intake hood painted with an arrow that pointed into a wall of roots thick as woven rope. Elias might have believed it if he had been alone. Mara tugged one root aside with the tip of the narrow knife already in her hand, using it to clear roots and probe seams as they went, showing solid wall behind it.

“False intake. False rescue marks. False drop signs.” She let the root fall back. “You get a few stories started up top about mouths in the dark and people vanish by themselves. Nobody asks who taught them the fear.”

Elias glanced up into the trunks. Somewhere high above, air moved through hidden fans with a tired, throat-deep hum. The conduit had its own weather. Warm drafts slid down one aisle. Cold air breathed from another. It would carry sound strangely, he thought. A perfect place to herd people by echo.

His mind kept sorting the place into systems even as another part of him bristled at the human design in it. Fear signs. Routing myths. Behavioral fencing. The same logic as the guide tones above, only stripped of comfort.

Mara halted so fast he nearly walked into her. She held up one hand. Ahead, in the dark between trunk rows, something gave a soft scrape and then went still.

Elias eased his weight back. The ringing in his left ear blurred the silence, turning the conduit into a pressure chamber of half-heard things.

Mara tipped her chin toward a maintenance collar at the base of a trunk. “There. Wire tag’s wrong.”