Most people have addressed breaking the canopy but ignored
If you just un-do your harness, won't you just flop and break your neck? What's the technique here? Naturally, we won't want to be hanging around upside down for long.
This was part of the Air Cadet brief for the Chippie AEF and said that you gradually loosen the straps until you were resting on the canopy before releasing the straps.