The hallway was long, with many turns and many branches. Unmarked doors, their color slightly grayer than the silver of the walls, lined the corridor. I figured we'd walked maybe half a klick when the corridor opened out into a kind of central lobby, with other corridors leading off in all directions. A mirror-finish desk that I guessed to be a nurse's station stood in the center, staffed by several officious-looking, white-suited staff.