I like calling flop bets with bottom/middle pair vs a preflop raiser in a 2-3 way pot, moreso when in position and on a drawy board.

a) he may have AK and you are ahead anyway
b) he may have AA/KK and you improve to 2 pair/trips and bust him
c) it looks like your drawing so you have a lot of bluff equity if for example flush draw completes