I'm far more worried about what Chika may do to the other girls than her relationship with Sensei, tbh.
I mean, she's threatened to destroy everything he loves:
To jump some girl if they hit on him:
To flay Ami and feed her skin to homeless people:
Etc.
There's a reason Uta and Futaba seem scared of her:
She's at least Ami level on the crazy meter, but bigger, stronger, and honestly, probably crazier. Ami's broken, but likely harmless. Chika is just scary. She reminds me of my mother, lmao.
Edit: Also kind of hoping that Chika doesn't see Rin as an enemy who hid things when the time comes.
Extra Edit: Keep in mind that even
Ami seems to think Chika may be the most obsessed out of all of the girls: