NL100SH bottompair+fd c/r is in multiwaypot, but other guy coldcalls

[skibbel]

PokerStars No-Limit Hold'em, $1.00 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

CO ($100)
Button ($85.55)
Hero ($180.55)
BB ($109.15)
UTG ($41.95)
MP ($22.10)

Preflop: Hero is SB with 3[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/spade.gif[/img]. CO posts a blind of $1.
UTG calls $1, <font color="#CC3333">MP raises to $2</font>, CO (poster) calls $1, <font color="#666666">1 fold</font>, Hero calls $1.50, BB calls $1, UTG calls $1.

Flop: ($10) 5[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/spade.gif[/img], 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(5 players)</font>
Hero checks, BB checks, UTG checks, <font color="#CC3333">MP bets $3</font>, CO folds, <font color="#CC3333">Hero raises to $17</font>, BB folds, UTG calls $17, MP folds.

Turn: ($47) A[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero ...

Guy had bought in halfstacked, 20/8/10/15/200h
seemed reasonable, has played tight.
This is always a set/2-pair hm?