A bell started ringing. She wondered if she’d caused this to happen by using the emergency exit. But the power was off, so it couldn’t be that. The bell was not an electrical device. It sounded like an actual, physical piece of metal being struck by a flailing hammer. The sound was thready and faltering, as though whatever contraption drove it was already on its last legs. For all that, it carried clearly through the still air of the valley.