"Exactly," she said, stepping forward and examining the door. After a moment, she taps it rapidly, numerous times, and the door swings silently open, revealing a large, round room, with six pillars supporting it, the room about forty feet across and fifteen feet high, the pillars about ten feet in from the walls. There's no sign of another door, but there is a large, tile mosaic dominating the floor of the room, between the pillars.