I don't mind this fold too much, depends on what sort of hands you think BB will call a push with. Breakeven's around top 18%, which is 33+, most aces, kings down to KTs or so. If he's tighter than that you're picking up equity, and if he's looser your burning equity. He probably shouldn't expect you to be loose enough to make calling 18% worth it (and if he knew your hand/range he should only be calling between about top 8-13%), but I wouldn't want to test whether he knows that most of the time.

Other factors to consider are how often he's stealing, and how timid the other two stacks have been in letting him. If short stack is playing scared and big stack is attacking him, I'm more inclined to fold until/unless shorty catches a hand and picks up some chips.