Found this searching for walk-in autoclaves (which is a terrifying concept on its own). Somebody clearly had a good sense of humor.
Let me add to the terror...
As they use nitrogen for the pressure, It's very easy to pass out from hypoxia if you are near -or- in an open one. Good luck hearing the the door-closing alarms when you are unconscious as the computer seals the chamber.
Buddy systems and O2 sensors are generally mandatory because of this.