TPTK big stack v big stack

[ThePershore]

$20 one r one add-on on stars, around 70 left, i think 45 paid, both me and villian are top 5. Me, villian and one other at the table are on around 30k, he covers me by around 300 chips. Other stacks on our table are much lower.

Reads: villian seems decent, mixing up his play. Has been attacking short stacks but playing tighter / passive against me and the other big stack.

e.g's of this are - limping in late pos with T9o, calling a 3.5x raise from the short SB and raising a weak bet on a K high flop and putting the guy all in on the turn (SB had KK). limping behind 3 limpers (he was on around 42k - me 13k) with KQo calling my 4x BB bet from the BB (AA) and putting me all in after a half pot c-bet on a K high flop.
a short time ago i raised in early pos, other big stack called and he flat called on the button with QQ. again the flop came K high and he shut down, checking the flop and flat calling the other guys timid turn and river bets (other stack had ATs and QQ held up).

Table has been quiet/weak, most raises go unchallenged by the smaller stacks. In the hand I raise in early/mid position, standard raise, with AK. Short stack goes all in (not very worried about him pretty sure I am ahead) and villian in BB flat calls. I flat call rather than raise pre flop as I have position, and fully expect villian to check to me on the flop, so if I miss I miss for cheap, and if I connect with the flop I might suck in a worse hand, expecting him to check / call with worse.

So anyway, HH is as follows:

PokerStars No-Limit Hold'em Tourney, Big Blind is t600 (7 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG (t17735)
Hero (t27630)
MP2 (t7512)
CO (t3860)
Button (t34152)
SB (t16411)
BB (t27980)

Preflop: Hero is MP1 with K[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img]
1 fold, <font color="red">Hero raises to t1500</font>, 1 fold, CO raises to t3810, 2 folds, BB calls t3210, <font color="red">Hero calls t2310.</font>

Flop: (t11080) 5[img]/images/graemlins/spade.gif[/img] T[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/spade.gif[/img] 3 players) BB bets t12600, <font color="red">Hero?</font>


WTF at his flop bet, what's his range here? Other guy is all in so is a zero side pot. I 100% expected to be checked to no matter what flopped so was pretty thrown. Is folding here gross?