I'd have to guess he fell accidentally. Suicide is pretty far out there. Way far.
I very seriously doubt that anyone who knows the slightest thing about parachutes and skydiving would rely on an AAD as the primary means of deployment. That's almost ludicrous.
Also can't imagine a pilot bailing out of a functional plane with hours of gas on board without coordinating the location and timing with the other pilot.
I have however known GA pilots to hang out of doors and try to fool with stuck landing gear, without a chute.