I guess the big question is whether Mashiro had Fuuko share her location to lure Yuni in, or if Fuuko somehow set it off on some slim chance Yuni would come find her. Mashiro's playing it cool either way, it would seem, so time will tell on that.
Very interesting to see Nanase so broken up over Yuki, though. A bit of a shame the actual fight happened off-screen like that, and we only get this aftermath with all of Nanase's "oh woe is me" self-indulgence. It does reinforce just how self-interested Nanase has always been, though, which is nice to see; even her "bestest closest bestie" was forgotten for half of their life together, all because Nanase only sees whatever's in front of her in the exact light and context she wants it to exist in, and doesn't seem to actually pay attention, otherwise.
Guessing there'll be another 3 chapters of this volume; so I'm curious if Mashiro will be dealt with and the arc involving her & Fuuko concluded by then, or if it'll carry over into volume 10 with the stakes increasing. She's basically directly involved with Fuuko only (and thus by extension Yuni secondarily), so roping Yuki & Nanase doesn't make sense at the moment. She's a big deal, being a major narrative plot point for one of the leads of the story, but I don't know to what extent she'll be intertwined outside of representing the worst of Fuuko's impulses and trauma.
Fantastically dramatic as always, though. And it's great to see Yuni crystallizing around what she actually wants and what she feels is important to her.
I absolutely love Nanase's mom though. That level of purity is so out of place in this series and it's just great to see her sticking out like a diamond in refuse.