I stop breathing. I feel my heart tighten in my chest, as if, for a second, every cell in my body just ceases whatever it usually does. I am lifeless. Iron, like the ring in the wall against which my wrist chafes, or ice. I am fear, and no other thought, feeling, or sensation registers. I had thought that not being sure was the worst thing I could feel here in the dark, but someone is there, and knowing that is far, far worse.