Blimey, that was an extravagant measure, mounting a whole Varsity fuselage in a rig just to test the rear door escape.
Not if you ever had to contemplate using it! The escape hatch was quite a narrow aperture and not the easiest thing from which to make a clean exit if the aircraft was not in reasonably stable flight. However we were told that the chances of survival were considerably better than risking a close encounter with the tailplane when using the rear door.
exmpa