Preflop
I dont like calling here with JTo. Maybe I could get on board with it, if it was JTs, since suitedness gives more
equity and playability. But even then its marginal, when UTG has made a large raise to more than 4BB. I would certainly also not 3-bet, so here I would just fold and not even worry about it.
Flop
Normally I would not bet full pot, but its a freeroll, and you are very deep, and for those reasons I dont mind it. Maybe you could even overbet, if you are going large? In NLH we are not limited to bet the size of the pot. UTG now check-jam, which is a little surpricing. But you only lose to sets, and you block 4 of the 9 possible combos. So its a trivial call, and I would not think to much about it, especially not in a freeroll.
Results
So he overplayed his KK but got there. Essentially just a bad beat story. The real study point here is preflop, where it seems like, you need to clean up and do some more folding.