The problem here is... well, there are a lot of problems here, that's part of the problem here.
The first part of the problem here is that it is very quickly becoming clear that any plan which relies on 1) Tommy having, and being able to provide, detailed or accurate information about anything, 2) Clay being willing to provide accurate information about anything, or 3) Tommy being willing or able to conceal from Clay that this conversation happened, is not a plan, it is a pipe dream.
From there it seems like the next move should be to talk to the rest of Manchester and demand to know why they're harboring a maleficer who's threatened one of Kyoto's freshmen, except that the second part of the problem is that from everything that's come up so far it really, really seems like that's just going to get the answer that none of them know what she's talking about and how sure is she that Ayako wasn't just spooked.
From there, the next move would be to go to the rest of the Anglosphere at large and make it publicly known that Manchester is harboring a maleficer who threatens freshmen etc, which just about every enclave is going to want to do something about-- it's really bad if one enclave suddenly gains from a war rather than losing everything-- except that the third part of the problem is that, well, Manchester has a maleficer, which means that they gain rather than losing everything if there is a war.
If it came down to a war between Manchester and Kyoto-- well, Hitomi is pretty sure Kyoto would win. Nobody wants to be in the version of the world where Manchester gets to do whatever they want because they have a maleficer senior. Nobody wants to be in the version of the world where enclaves, in general, get to harbor maleficers who in turn get to threaten everyone else.
Pretty sure is not, in fact, sure enough. Graduation is in seven months and if there's a war none of the Kyoto seniors graduate and probably most of the juniors don't either, they need to be focusing on graduation and not using enormous amounts of mana on fighting Manchester over an indie freshman who's not even allied with them, that's part of keeping her people safe. Graduation is in seven months which is not, if you think about it, that long to wait before Clay graduates and the problem solves itself.
Except it doesn't, actually, because if one enclave gets to go around threatening the others because they have a maleficer and nobody will confront them about it that's not in fact the kind of situation that just goes away, and another part of keeping her people safe is that she needs to not leave the juniors an unsolveable problem because she couldn't be bothered to figure it out herself.
And whatever she decides she has to decide it right now, because Tommy is not going to be able or most likely willing to keep from Clay that this happened and if they try to keep him away from Clay entirely that'll also be parsed as escalation.
Graduation is in seven months and she's so tired.