Flopping Middle Pair - What to do ???

[graarrg]

GRUNCH ATTEMPT:

Flop: good bet out, I would do the same 4-way. Calling the CR is fine.

Turn: Sigh, this pot is so big it makes me cry to fold AND to stay. It would depend on my read of BB I guess.

River: Definite check. not only do you have a potential checkraiser ahead of you, you have a passive player who has called down to this point and who cold called two before the flop.

BB looks like he had J3, or maybe even 33, and MP3 either KJ, KT, or potentially a Q-rag. What else would he cold-call with? then again, he might cold-call with anything. Caught in between someone pumping the flop and the possibility of the king out there, I'd check the river. And check/call by instinct.