AK Facing weird Bet in Reraised Pot 5/10

[fearless2k]

effective stack sizes ~1200 one short/Med stack @ 700
6 max game

UTG Min Raises to 20 (slight donkyish player so i decided to isolate)
In second Position w A [img]/images/graemlins/diamond.gif[/img] K [img]/images/graemlins/club.gif[/img] Reraise to 90
P3- Fold
P4 Calls 90 (short stacker . Not too worried about this call, could be small pair or junk like QJ/KJ)
SB- fold
BB Calls (alarms went off as i considered this player decent lag that "should" know i dont reriase light in second position)..dont take this statement too heavily as i dont consider that player the better then average at 5/10 from what i have seen.
UTG calls

FLOP
Q [img]/images/graemlins/spade.gif[/img] A [img]/images/graemlins/heart.gif[/img] 5 [img]/images/graemlins/spade.gif[/img]

BB bets out 240 into ~350 pot..
UTG Folds
Hero? I have BB covered (BB has another 700 after making this bet) Is this insta muck?

[jj12]

yeah I would fold. I think you are chopping / behind and a good lag wouldn't be messing around with a bunch of donkies in the pot.