Many of the main characters are homages to films that inspired Mental: Tom, Dick and Harry are the names of the tunnels in The Great Escape. Blythe was the forger in The Great Escape.
In the establishing shot of the common room a tall patient is sweeping the debris of the fallen vent, this is a nod to the character Chief in One Flew Over the Cuckoos Nest.
The entire film was shot on less than 2400' of 16mm film.
Despite the film being set in the late 1950s, a modern Lexus SUV passes through the background of the scene at the main gate while Dr. Seppel, Dick and the Orderly are loading the trunk into the Taxi.
One L shaped vent was used for all the shots in the opening escape attempt. It was repositioned and lit differently to give the appearance of several different vent sections.