So you can pull a switch up part of the way then im assuming so anyways...
when a person goes there they pull a switch down and its always that switch, unless they have been there already in witch case they would pull the switch of the oposite wall, so when the switch that woudl be pulled to show hwo many guys has been there has been pulled 23 times one of the guys is chosen to ask the guards. and since it will have been pulled 23 times everyone woudl have been there and they would get it right and get out, or they could kill the guards and leave while being taken to the jail...or wait for a rescue