I just thought of something else about this (couldn't sleep last night

).
Most people, having flopped a full house would choose to slowplay it and flat call. Even though there's two players in the pot with you here, a flat call (rather than the check-raise) would still have been an option; realistically, if you're putting the original raiser on an overpair (a good scenario for you!) and the check-calling CL on a draw of some kind, you know that the original raiser is likely drawing to two outs and the chip leader is drawing probably almost dead with his flush draw/straight draw/whatever he's got.
Now - here's the point: if you flat call the flop bets... then the turn comes down with another 5. Horror! Terrible card, because now your full house has been counterfeited, you're basically playing the pair of threes and anyone with a bigger pocket pair is beating you.
From this position, you have gone from slowplaying a monster to suddenly being extremely vulnerable; you might curse and grind your teeth about it but at least you can likely get away from the hand if there's a lot of action. Not good news when you'd been expecting to make a lot of chips on this hand, but at least you still have 47k to make a comeback.
Alternatively, if the original raiser has overcards but not an overpair, and shows any weakness, you can bet and maybe take the pot right there. Whatever draw the chip leader was on, he has to give up now because of the trips on the board and the possibility of drawing dead vs. a pocket pair higher than 6's. Of course, the problem now is that the pot is huge and you only have 47k to chase them out with, but it might be achievable.
Just another viewpoint.