Lock

The subtleties of the shifting rooms were what made them just as they were before they were even altered at all, closing off any of the entrances and exits the moments they were all transitioned to and from all simultaneously by the group, whomever and whichever they would be. Though they all seemed to be in the same room, all were actually in different places and when they walked outside of their respective Trap Rooms, they each would see a Window with Baby Evil inside of it at the end of the Hall and Doors that were placed exactly where they once were in the beginning, as if nothing had changed. This was if they could even exit the rooms at all, which were all locked behind them upon entry, specifically for the sake of disallowing them escape even after they might have done so, if at all. Thus, the Trap Rooms were sealed and all of the people within were set in place for Baby Evil to have its Fun with.