The way you describe seat2, he could have any two cards - and QQ smashes most of his range.
Given the animosity from seat4 to seat2 as you described, seat4 could be 3-bettng a very wide range here.
Flat calling with QQ is a mistake - you need more info before you play a flop. Couple that with the fact that QQ is the third best starting hand, and is most probably ahead here, you have to re-raise.
If seat2 shoves, I think a call is reasonable. If seat4 shoves, I suspect AA/KK and I fold.
If both or either flat call, I"m ready to get my stack in if the flop shows no K or A.
Any K or A on the flop after their flat call, and I open or raise in position to see what happens.