Which, unfortunately, is the problem. Best I can come up with is if Twila stays in her hosts, the Malnosso will likely do a lot worse than what we can do to ourselves to 'fix' the situation. But since we're just hosts and she won't suffer for it, that's not exactly a compelling argument. 'Behave, or we'll put you back in the box' isn't going to be any better.

And I can't blame her, not really.

The hosts, I'm assuming, have already been given reasons for her to stay that likely pick at the most important thing for them. Other than 'do you really want another entity piloting you?' as an argument, I don't have much to go on, there, either, because whatever made them open up in the first place is still going to be there. That part, unfortunately, I think they'd have to shut down on their own, or get the help of people closest to them to see why they don't need the extra help from Twila.