[contentless]

Should take the free showdown. You'd be forcing out KK-TT with the river bet, but I'm not certain that pre-flop play indicates those hands. By the river, the pot is sufficiently big that MP2 calls with any sort of pair or bigger, so the river bet isn't for value or to win the pot.

I'd probably call the flop, and raise the turn for the best chance of taking the pot down, and evaluating the situation immediately. With a turn raise, if that doesn't take the pot, the situation has change and now the river bet might, and any KK-TT must be thinking about the pre-flop 3-bet.

Edit: Oh yeah...I'm new at this. So I'd appreciate it if other people constructively criticize my thoughts as well.