Revealing mistake: Pretty much throughout the whole show, the iron prison doors do not have any way to lock. Guards put the key in, but there is no actual lock or latch on either side of the door. Even when these doors are pushed shut, there is not a locking sound.
Oz (1997)
1 mistake in show generally - chronological order
Starring: J.K. Simmons, Ernie Hudson, Terry Kinney
Augustus Hill: OZ. The name on the street for the Oswald State Correctional Facility, Level 4.