One thing I don't see anyone saying about our first Phil-in-the-Wild fanfic is that, if true, Kat looking scared every time someone comes to interact with the pig suggests to me that she knows him as a violent person. Not saying he's giving her a black eye every time someone sneezes in the grocery line, but that she has reason to believe his big boy chest thumping has any truth behind it.
She's expecting him to pop off. Does this mean he has in the past? Or does he just spend his whole time with her talking about all the 11 year olds he's pimp slapped in real life? The latter is most likely, but just a possible glimpse into their relationship dynamic.
I doubt that when the whim strikes her, Kat will not hesitate to flee the gout palace, it seems like she's done it a few times with how sketchy her past is. Someone like that is used to people entering and leaving her life fairly easily, even if she's scared of them or even respects them.