[bozlax]

I just went through a whole semi-bluffing argument yesterday (in which I was taking your position, btw), and am just reading the semi-bluffing section in TOP, so I'll try to get this right, but basically:

By showing strength on this flop, with a hand that's not currently likely to be best, but has the odds to improve to the best, and then coming strong to a show of weakness on the turn, you're putting pressure on the Villans.

You're probably not going to lose your maniac, regardless, but he's just dead money, anyway. MP may, in fact, be bluffing the scary board, hizownself.