Your AT might've been the 'right' play (I couldn't tell you because I don't know the particulars of the hand). Typically in an MTT if your stack falls to 14-22 bb's, this is a good size stack to be looking to make 're-steals' (if an opponent is quite aggressive preflop & has been raising alot in LP to pick up the blinds, look for a spot to ship it over their raise in an effort to 're-steal'). If you all below this stack size you're basically looking for spots to either ship it over a raise with a big hand, or ship it allin preflop if you're first into the pot & you figure blinds are fairly tight (sometimes it's better to play the player when shipping it in as opposed to playing your cards).
Congrats on the game!! Well done!