In the 10th in Bad Toelz, we had a one man chamber. It was collapsable into a trunk about 4X4X4 ft. It was meant to do until the patient could be moved to a larger facility. If you have ever had an MRI or CAT Scan imagine being pushed into the chamber, only smaller, and having the hatch shut .
We also used it for pre-SCUBA testing. The committee chief, (Evil Gil Secor,RIP) decided to combine the test with a test for claustrophobia. The only way to fit into the chamber and still be able to equalize your ears was to cross your arms over your chest (body in a coffin style).
Not only were quarters extremely tight and reminiscent of a coffin but they left the light off and blacked out the window -- total blackness.
There was always at least one applicant who would go completely berserk and we would remove the cover off of the view ports, and bring him out and send him back to his unit.
I'm sure that if you looked, there would be some pretty deep fingernail scrapes on the inside of that chamber.