I move slowly along the passage, the phone held out in front of me. The faint blue glow from the screen is just enough to keep me from walking into the walls. The corridor twists and turns ahead of me, and after five minutes I've already completely lost my bearings. I have no idea which direction I'm going or where I might end up. My only consolation is that there's only one way back, so it's unlikely I'll get too lost.
As my eyes adjust to the darkness, I begin to notice other details. At regular intervals along the walls, for example, I start spotting small, nondescript door handles. Some have even been brushed with pale paint, making them easier to spot among the shadows. I stop at one and give it a wiggle. The door creaks open, revealing the dark room beyond.