98% to win post-flop bad beat

550 player online freeroll MTT exactly half way. M>20, Q ~1.5. Winner receives a trip to Vegas.

Hero dealt A [img]/images/graemlins/spade.gif[/img] T [img]/images/graemlins/spade.gif[/img] on CO.
Folds around to me, raise 3xBB. All fold to BB-Donk who calls.

Flop:

Q [img]/images/graemlins/spade.gif[/img] 6 [img]/images/graemlins/spade.gif[/img] 3 [img]/images/graemlins/spade.gif[/img]

Donk bets ~1/3 pot. I call.

Turn:

K [img]/images/graemlins/diamond.gif[/img]

Donk bets ~1/3 pot. I call.

River:

6 [img]/images/graemlins/heart.gif[/img]

Donk bets ~1/2 of pot. Pot is now size of my stack. I push. Donk calls and has me covered (barely). I don't see any other play unless I'm scared of K6, Q6, 63, or 66 which I'm not.

Results in white:
<font color="white"> Donk holds Kc6d for 6s full of Kings. I finish 275.</font>