Then why does D.B. Cooper's bail-out keep coming to mind?
DB Cooper bailed out of an aft stairway on a 727. He also demanded that the cabin remain unpressurized and he bailed out at a relatively low 10,000 feet, with the airplane travelling at a very slow 120 mph.
After DB Cooper used an airstair to escape from an aircraft in mid-air, Cooper vanes were installed to prevent an aft stair from being deployed in flight.
That was from the rear air stairs door on a 727. They were controlled from the cockpit. After that incident in 1972, the rear door and stairs on all 727's were modified to make them inoperable in flight. Have you flown on a 727 recently? Just about all the 727's still in airline service at the time of the 9/11 terrorist attacks in 2001 were retired by the end of 2001.
Cooper bailed out below 10K.