Thanks for the responses guys. Glad to hear there are more experienced MTTer's who'd play it the same. I did 4bet to give the false impression of fold equity with the intention to call off. Low and behold he shoved, I snapped, he showed JJ and it held.
I don't normally want to be getting it in pre this deep w AK but against this aggro sb it was a must. I guess even the most aggro of aggrotards wake up with a hand sometimes!