That is awesome. Strangely, almost this exact thing has come up before in my games. I said that the beasty was unable to make its breath attack as per normal. The paladin had the option of intercepting each attack it tried to make. In the end, the paladin took 3 breath attack rolls onto himself, saving the party, but learning that it is not good to be stuck in the throat of a firebreathing dragonish thing.
At the end of the attack he was spat out and pushed 6 squares. The cool thing is he made an acro roll and ended up rolling onto his feet ready to charge, rather than sprawling out like a mess. His initiative was the very next action, he charged back in, bloodied it and as a triggered response it swallowed him again...
This prompted a player to comment "I think he likes it in there." Had us in hysterics for a while.