Multiway pot, big bets and a baby set

The table has been generally passive with many people limping in to see the flop. SPecific reads below.

Ultimate Bet No-Limit Hold'em, $.50 BB (10 handed) FTR converter on zerodivide.cx

UTG+2 ($28.70)
MP1 ($27.40) - SLA (30/8/4)
MP2 ($21.65)
MP3 ($16.15)
Hero ($47.50)
Button ($47.55)
SB ($24.05)
BB ($81.50)
UTG ($8.75) - Recently sat, bought in VERY short
UTG+1 ($75) - Rock, 18/3/1

Preflop: Hero is CO with 6[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/club.gif[/img].
UTG calls $0.50, UTG+1 calls $0.50, <font color="#666666">1 fold</font>, MP1 calls $0.50, <font color="#666666">2 folds</font>, Hero calls $0.50, Button calls $0.50, SB completes, BB checks.

Flop: ($3.50) T[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(7 players)</font>
SB checks, BB checks, <font color="#CC3333">UTG bets $3.5</font>, UTG+1 calls $3.50, <font color="#CC3333">MP1 raises to $17.5</font>, Hero ???

The short stack in back of me doesnt worry me - he's gonna push, no doubt. The rock already called a pot sized bet in EP. The SLA - who knows?

WWYD?