KK on button

[bigbaldguy]

playing in $50 tourney, started with 975 players down to 172, top 152 get paid.

Normal table..... 3 to 4 times bb raises preflop, no super aggressiveness, last few hands alot of folding preflop.

Here's the hand....

Blinds 200 - 400 antes 50 full table (9)
UTG (16,000) raises to double - 800
2,3, and 4 fold
player in #5 position (13,500) calls
#6 folds
I am on button (12,500) with K [img]/images/graemlins/spade.gif[/img] K [img]/images/graemlins/diamond.gif[/img] I reraise to 2800
blinds fold
UTG calls and so does #5
pots 9450
flop comes Q [img]/images/graemlins/club.gif[/img] 10 [img]/images/graemlins/club.gif[/img] 4 [img]/images/graemlins/spade.gif[/img]
UTG checks
#5 bets 2000
I think for a minute .... maybe he has AK [img]/images/graemlins/club.gif[/img] or AQ or JJ and putting out a probing bet....so i decide to go all in for my final 9800.
UTG folds
#5 calls
He turns over 4 [img]/images/graemlins/heart.gif[/img] 4 [img]/images/graemlins/club.gif[/img] for a set
his hand holds up....
so....
did i do anything wrong.... should i of raised to say 3600 -4000
or did they just make bad calls to my raise

any info would be great.
thanks