Live Tourney - Very Tough Spot

[9cao]

This hand occurred in a live 130 person tournament last week at my local casino. The hand is still bugging me so I would like to get some feedback.

The tournament is down to 40 players (top 15 pay) and we just had a break so I know that I am 2nd chip leader, with chip leader seated to my immediate left. He is a total donk and has seen chips fall into his lap despite his play. There are about 300,000 chips in play. I have about 22,000 and he has over 30,000.

Blinds are 150-300 with a 50 ante. I am in the SB with As2s. Folded to button (about 7,000) who limps, I complete, and BB (chip leader) checks.

Flop comes AT2 with 2 diamonds. I check, chip leader bets 1,000, and the big blind calls. I serioulsy thought about folding right there but decided to declare (not literally) I had 2-pair and raised to 4,000. BB, almost instantly says raise you 20,000. Button folds quickly.

Now the only things I know for sure are that this guy would raise AA, TT, 100% preflop. I also have a suspicion he would raise AT in that spot but I can't be nearly as sure.

Any thoughts?????