losing to a 2-outer on the turn?

[spahk]

from party 200. full table.

my stack: 406
mp's stack: 514
button's stack: 449

i'm UTG+1 with Ac6c and limp in. a few more people limp, villain on the button makes it 6 to go. i call, 1 player in mp calls. 3 to the flop.

flop (20) Jc 2c 8d
i check. mp leads for 20. button calls 20. i raise to 100. mp folds. button thinks for a long time... and calls!

turn (260) Ah
i immediately push.

any thoughts?