"If I were to guess, I'd say they were in some kind of vault," said Twilight. "Maybe through there," she added, pointing to a door at the far end of the room. She teleported over to it and peeked through, finding a set of stairs that went down below ground level. At the bottom it opened out into a small area, with a large steel vault occupying one end of the room. "Bingo. Now we just need to get in."