Should I have lead this flop?

[FreakDaddy]

Party Poker No-Limit Hold'em, $ Hero (9 handed) converter

saw flop|<font color="#C00000">saw showdown</font>

SB ($27)
Hero ($24.50)
<font color="#C00000">UTG ($62.85)</font>
UTG+1 ($39.10)
MP1 ($22.10)
MP2 ($19.23)
<font color="#C00000">MP3 ($6.25)</font>
<font color="#C00000">CO ($12)</font>
Button ($6.97)

Preflop: Hero is BB with 2[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/heart.gif[/img]. SB posts a blind of $0.10.
<font color="#CC3333">UTG raises to $0.5</font>, <font color="#666666">3 folds</font>, MP3 calls $0.50, CO calls $0.50, <font color="#666666">2 folds</font>, Hero calls $0.25.

Flop: ($2.10) 6[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/spade.gif[/img], 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
Hero checks, UTG checks, MP3 checks, <font color="#CC3333">CO bets $2</font>, Hero calls $2, <font color="#CC3333">UTG raises to $4</font>, MP3 calls $5.75 (All-In), CO calls $3.75, Hero folds, UTG calls $1.75.

Turn: ($21.35) 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players, 1 all-in)</font>
<font color="#CC3333">UTG bets $6</font>, CO calls $5.75 (All-In).

River: ($33.10) 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players, 2 all-in)</font>

Final Pot: $33.10

Results in white below: <font color="#FFFFFF">
UTG has Kd Kh (two pair, kings and sixes).
MP3 has 5d Ah (one pair, sixes).
CO has Ks 6s (three of a kind, sixes).
Outcome: CO wins $32.85. UTG wins $0.25. </font>