For Jin's second speech bubble on page 5, it's not "ant". アリ in this case is slang coming from ある or 有り得る, with similar usage.
In this case, "何でもアリだ" would be something like "anything goes" or "anything can happen".
So the full phase should be something like "what's more, anything can happen in God's Dungeon.'
edit: added full phrase translation