If the elevator is stuck then which way up you are is not going to make

any difference to the force keeping you in the cockpit -- only speed is.



Rolling inverted is going to put you into a half loop, with the initial

G force the same as it was the right way up, and then buiding.

Not entirely true, he may have had a little elevator, or some elevator with very heavy control resistance, and took planned departure at minimum bailout altitude rather than chance landing and losing elevator entirely below 1000'.

I agree though that damage may have contributed to the roll and that it may not have been not 100% intentional!