Here we see one of Callie's party tricks: Being swallowed along with someone and then swallowing them inside the other pred. This is one of the ways she avoids getting immensely fat despite eating several people a week. Another is swallowing someone and then finding a helpful pred to eat her. She does digest people often enough, but if it weren't for her little tricks she'd either have to cut way back or she'd get huge very quickly.