From inside the toilet the thing that looks like the exit door - delightful and substantive four panel - is not exit/entrance door but in fact the cupboard. There's a wonderful sign near the handle saying as much....'This us a cupboard not the way out'. The actual exit is a more plain affair, flat with a run handle and grab rail. So the visual clues are less.... with the cupboard there are fur panels and and handle to naturally draw you.
To help, as well as the negative "don't use this door message", how about a positive "This is the exit sign" on the real exit door.
