As a somewhat weird analogy, it feels like Missy, instead of being given proper rehab, has been forced to go cold-turkey and everybody refuses to even consider that this might be hurting her more than helping her, even though it's obvious that the drug of being a child soldier is a bad thing.
I was so very tempted to make that analogy in my post a few pages back, but I resisted.
it isn't up to him. He's obligated to color inside the lines.
And nobody in the protectorate has bent a few regulations? Looked the other way when itchy Wards went on solo patrol? Unofficially left out information on
relatively safe locations that they couldn't send Wards but couldn't justify full Protectorate members?
Granted, it's my (second hand) understanding of his character that he
wouldn't think of those things, but they're options that other Protectorate leaders might have thought of.
I mean, at the core of it he's in the right on several levels. He has a moral obligation, he has rules and regulations tying his hands, but the thing is it seems pretty clear that he's not actually tried to communicate with Vista on these things. If he has at some point got down, sat down full seriousness with Vista, explained to her exactly what the problems are and discussed how to meet in the middle, I'd respect that at least, but...
From how it sounds, taking both their testimonies into account, It sounds to me like Chevalier has been making declarations without any explanation and with no attempt to find any sort of compromise. He's just going 'my way or the highway' and putting everyone else before Vista on the sole basis that she's a problem, which is frankly the exact opposite of what you want to do.
Work more closely with problems to try and help them stop being problems. Don't push them away, it only makes everything worse.
Vista seems to be equally intent on being knowledgable of the regulations in order to know when to break them. Sitting her down and going over line by line WHY he can't let her do the things she wants would at least redirect her anger from him to the system.
("You want to go on a solo patrol? Here's Rule X, Paragraph Y, Line Z that says I
can't let you do that.")
It also opens the possibility of her finding loopholes he didn't.
("Yes, but Rule A, Paragraph B, Line C says in such and such circumstances* you can ignore rule XYZ")
*Such circumstances might be such an occasion as
not having enough Protectorate members to escort the local wards. (Which is really something they should work on, either transferring in more Protectorate members, or incentivizing Wards to transfer out.)
It's probably too late for him to do that, but if he'd done that a few weeks / months ago when it became obvious she was chafing at not being allowed to fight he could have redirected her anger to better act as a mediator instead of a target.