tartare, indeed. The door jacks were operated using high pressure air. There was a metal lid that gave access to a T-handle, pull this and the door would close. It was not unusual for the crew chief to give it a heave. Near this was a handle with black/yellow knob. Pulling this would unlatch the door and it would drop open under gravity. Pull it through the detent and it would be blown open against the air flow for abandonment.
A later mod provided a switch at the plotter's station to do the same thing. The plotter had a fixed seat and had to egress after the radar or AEO had swiveled their seats.