[Fantam]

BB appears to have most likely been betting and raising the flop with 2 pair, such as QJ. A set with 33 is also a possibility.

MP2 limp/3-betting preflop suggests that he might have had AA or KK. However, I would not have expected him to just call on the flop with those hands. When MP2 raises on the turn, the most likely explanation seems to be that the 7 helped his hand. Therefore the most likely hand that he might also have 3-bet preflop with (being loose and agressive) now seems to be 77, and that he just made his set on the turn.

If it was likely that you were only behind to 2 pair on the turn, then I think that it would have been correct to call for the chance to improve to a better 2 pair or set by the river.

However as it seems that there is a reasonable chance that you are behind to 1 or maybe even 2 sets, then folding to the turn raise makes sense. I would have felt inclined to fold to MP2's first turn raise.