fold set of 2's on the flop?

[snapfc01]

2nd hand of one table sng... no reads
limp in mp with 22(i know some would disagree with even playing this hand from mp however i have my theory on the subject and my question here is purely post flop play)
blinds are 10/20
5 limpers... as there often are in early rounds of sngs...
Pot=100
flop comes A [img]/images/graemlins/diamond.gif[/img] 2 [img]/images/graemlins/club.gif[/img] 3 [img]/images/graemlins/diamond.gif[/img]
sb checks... bb bets 60... i raise to 240... mp+1 reraises to 480... button folds... sb folds... bb calls... i move in... mp+1 calls bb calls...

bad raise? the only hand i can be afraid of i think is the bb having 45 or the mp+1 having 33 however i think it is much more likely to see two draws or amybe A3... any thoughts?