Where is Sarah?

"Hey, what the hell happened?" Sarah asked. One moment, she was out on the street, with that loser Jon, his dumb friend Karyn, and frickin' Santa Claus, then the next, she was inside a room, somewhere. Looking around, it was very dark, but at least she seemed to be alone at the moment. No weird creatures lurking around. But then she heard footsteps and froze. A moment later, she heard a door opening and spun towards the sound. So who was coming into the room?