[brian64]

Given BTN's play doesn't it seem likely that he had a set, or maybe top two pair? If so, he must have been really happy to get a free card on the turn. UTG+1 also got a free shot at a wheel. How about betting 1/2 pot to protect your hand?

Also, sorry if this is a non sequitur, but isn't UTG+1's play pretty loose here? Even on 6-max I wouldn't limp with 34JK rainbow preflop, and I don't think I would call the pot bet on the flop either. I think it's a tough decision on the river, which is why it's better to muck 34JK preflop.