The dark goes on forever, or so it seems at least. The heavy breathing of my rescuer tells me I’m still on the right track, but there are no features in the tunnel to tell me where we are or where we’re going. The walls and floor are made of concrete, or perhaps very closely fitted brick. The air is stale but breathable. I’m reminded of a video I watched some time back where an archaeologist sent a tiny robot up an air shaft in one of the pyramids, only this time I’m the robot. For the life of me I can’t remember whether or not they got the robot back out.