Hmmmm.

Or she felt responsible for the actions and left the school?

None of the above

I read the novel and no, she disappears for other reason.
(SPOILER)
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She's kidnaped by someone one we already know, because he's the master mind behind Katarina's accusations and she notices he can use dark magic (to control the students minds) and he had some kind of resentment towards Katarina because...reasons. Yeah, I don't want to ruin the surprise.

I see.so that's the reason.
Thanks for sharing.

where did you read it and can you give me a link?

I don't minf. Ruin it for me ლ(´ڡ`ლ)

https://www.novelupdates.com/series/i-reincarnated-into-an-otome-game-as-a-villainess-with-only-destruction-flags/

THANKS!!!

Np. It's a really good translation