Finding the Fold Button with AK?

[imported_leader]

SB is tight and fairly passive 20/4/.7 over 79 hands
MP3 has managed to find 9 hands to play out of the 11 he's been at the table.

Party Poker 2/4 Hold'em (10 handed) converter

Preflop: Hero is CO with K[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/heart.gif[/img].
<font color="#666666">5 folds</font>, MP3 calls, <font color="#CC3333">Hero raises</font>, <font color="#666666">1 fold</font>, SB calls, <font color="#666666">1 fold</font>, MP3 calls.

Flop: (7 SB) 7[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">MP3 raises</font>, <font color="#CC3333">Hero 3-bets</font>, SB calls, MP3 calls.

Turn: (8 BB) 5[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, MP3 checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">SB raises</font>, MP3 folds, Hero...

In the heat of battle I called, but I think that him calling the 3-bet and CR'ing the turn should have been enough to send this one to the muck. What do you think?