Crawlers previously ejected from the dungeon, the precedent Carl half-wishes for Katia.
When Carl weighs the possible outcomes of Katia eating the Orchid of Eileithyia's Grace, he notes that the pregnancy prize would see her literally kicked out of the dungeon like the Popov brothers.
He knows that outcome is not what Katia wants anymore — but part of him thinks it would be better, because it would mean she was free.
The precedent for crawlers ejected alive from the dungeon.
Also appears in books you've already read — spoiler-safe to their endings: