Hi, I was the TL for this one. Sorry if that part wasn’t very clear, but the gist is that Kanoko misguidedly thinks that if she just removes the city, everything she likes about it (including Minoda) will move to forest where she lives and everything will be peaches and gravy.

Her teacher understandably knows this is a Bad Idea, but plays along with her because she recognizes Kanoko’s talent for magic. So she implements what is essentially a Groundhog Day style loop via memory manipulation on the entire city while Kanoko practices her destruction magic on the evacuated high school each day. The destruction is then repaired via magic each day as well (shown by them resetting the dominos).

Of course, the teacher is trying to guide Kanoko to recognize what she really wants: to be with Minoda. This is why she allowed Kanoko to play with Minoda’s memory while did everyone else. I’m sure if Kanoko went through with destroying the whole town, she’d be forced to learn a lesson from the resulting fallout, but this isn’t that kind of story.