[Lloyd]

What you're talking about is a probing bet and is very useful when you are first to act (or checked to you on the flop) and you think the flop missed your opponents. It is most effective against a single opponent since there is an increased liklihood that it did hit someone with more people in the pot. Against two opponents, with this type of flop, it's certainly worth a shot.

The appropriate size of a probing bet is around half the pot. In this case about 2200. You WAY overbet the pot (4400) with your bet of 6400. Unless you or your opponents are pot committed, there is rarely a reason why you would bet such a large amount, especially with a middle pair. A half pot size bet is large enough to chase away speculative hands that missed the flop, and charge draws enough that they aren't getting odds to call (for example, with two overcards they are about a 6.6 to 1 dog to hit a pair on the turn and you are offering them 3 to 1 odds).

Now if you only bet 2200 versus 6400, your opponent's raise would be offering you far worse than 3 to 1 odds. Regardless, you are most likely behind at this point and would have to hit a set to win. You're about an 11 to 1 dog to hit your set on the turn or river. Even accounting for the chance that he has overs and you're ahead, I don't think you're getting good enough odds to call and put your tournament on the line.

I would fold.