So I was thinking about an idea to add an Elevator to the game and dismissed it because it would break the game by making things too easy but I noticed an elevator in the Foyer image. Maybe the elevator should have an "out of order" sign on it... the acrobat might be able to climb the elevator shaft and/or maybe there could be a tool to use the elevator shaft to get between floors.
I'm also thinking of a using a rule variant where the players start in the Foyer. When laying out the floors during game setup the the 3 foyers would be set aside and the remaining 15 cards for each floor laid out. When the players choose a starting location (on the outside wall) the room in that location is replaced with a Foyer and the displaced card moved to the empty space on the first floor. The 2 remaining foyers would be placed above the first floor Foyer so that all the Foyers are in the same location on each floor. Logically the stairs should all be stacked to but doing so would make things too easy.