how did i play this

I wasn't watching, so I'll just take your word that he was a bad player. If this is the case, you probably can find a better spot to get your money in than this. I would think this especially true if it's already down to three and the blinds are only 25/50. That said, you were calling 2050 to win 2975 with the better half of a coin flip. You got unlucky. That's probably what you wanted to hear.

The A2 is behind ANY pocket pair, not just a 5 or 6. I agree that the bluff there is not unreasonable, but it's only a good play if you know the opponent will fold. It's a little better with AK, AQ, or KQ, where you think any of 6 outs on the river will make a winner if you're called. I wouldn't indict the player like the OP does, but I'd guess he made other bad plays for OP to label him so strongly.

Ok, he raised 3x the BB preflop, you min raise him and he goes all in. You are only substantially ahead of 66-22 moderately ahead of Ax where x is < 7, and a coin flip against anything down to 89 suited. Do you really want to risk your entire tournament on the bubble on that kind of a coin flip? Blinds at 25/50, you still have over T2000, no reason to be coin flipping. Wait for a bigger hand.

Pushing all in is almost always better than calling all in (Note, I'm not advocating a push all in preflop), and if he is a gambler, you can catch him in a situation that is much better for you.

Aodhan

In this case, AA, KK, possibly QQ. Anything else there I dump and lay in wait.