After stepping out of that spinning room, the door closes and locks behind you. A hallway leads you away from that room. At the end of the hallway, you come to a small room with three switches on the opposite wall. There is also a door on your right, but there's no way to open it. Perhaps one of the switches on the wall will open it. But which one? There's only one way to find out.

 

Switch 1
Switch 2
Switch 3