Does the bag get destroyed though? In real life a cloth item wouldn't be destroyed by being squeezed during digestion/peristalsis. The stomach acid would work on the bag, of course, but how would that affect a bag of holding; wouldn't a magical item be resilient? I don't recall any rules regarding this specific (bizarre) situation. Also, if the bag is destroyed, the items within are lost forever, presumably stuck forever in their pocket dimension, but what happens when one of the items is a sentient creature?