Zula painted the light beam up and down the length of the door crack, and noticed, way up at the top, a steely glint. Piano wire. It had been made fast around the vertical bar that served as the edge of the door, and routed horizontally across the gap between door and frame, across the grid and all the way to the tunnel wall. There it disappeared into a mound of trash that had been piled up in the corner formed by the wall and the steel grid.