Just to add to the believability of Kouko's rampage and the sudden confession, in the LN, they were both pretty drunk.

It seems the anime version will cut out all the alcohol, so I suggest that if you see something hard to believe, it is probably because they were drunk in the original text.

The anime pace is amazingly fast. It'll probably catch up to the translated novels in the next episode or two. That is great, because the translated text is harder to understand than moonspeak.