How risky is not 3 betting this flop ?

[BubbleMint]

Typical 2/4 game, very passive fish, I am by far the table aggressor.

Button is a solid player, cold calling 3bets is not typical for him. With the cold call, I thought he had to have 10,10-QQ, I am sure QQ+ he caps.
He plays well normally and is a winning player over about 600 hands.

BB is a terrible passive fish, if he raises he has something, otherwise he is happy to call down bottom pair.

Full Tilt 2/4 Hold'em (5 handed) Full Tilt Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is MP with A[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">UTG raises</font>, <font color="#CC3333">Hero 3-bets</font>, Button calls, <font color="#666666">1 fold</font>, BB calls, UTG calls.

Flop: (12.50 SB) A[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/heart.gif[/img], T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG checks, <font color="#CC3333">Hero bets</font>, Button calls, BB calls, <font color="#CC3333">UTG raises</font>, Hero calls, Button calls, BB calls.

When I am check raised by the pre flop raiser on a flop such as this, I tend to instantly think, 2 pair or set. Should I raise the others out or try to built a pot where I have nice equity ?

Turn: (10.25 BB) K[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG checks, <font color="#CC3333">Hero bets</font>, Button calls, BB folds, UTG calls.

River: (13.25 BB) 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
UTG checks, <font color="#CC3333">Hero bets</font>, Button folds, UTG calls.

Final Pot: 15.25 BB