This has probably been asked before, but the search facility here ... let's just say it needs improvement.
Assume Corbin was swallowed while at full health (8). At the start of his turn, he rolls 8 power dice and none are blanks. This is one 'attack' that deals 8 wounds and Corbin only takes 7 of them; now he's down to 1 health. Next turn, Corbin rolls 1 power die; regardless of the result he can ignore the wound.
So does Corbin just run up and say "Come on! Eat me! I'll rip you're insides out!" and, if swallowed, just use his single red die (or other one-handed weapon) to eventually kill the monster?
I noticed a similar question was asked about using shields while swallowed.