>>534521886
The "sudden change of heart" ultimately stems from Aris' conflicted feelings given that she's very visibly being coerced and led astray by Rio's overly rationalizing approach versus her wishes to not hurt anyone. It's hardly a light switch compared to the other volumes.
And no I did not ignore sensei's passive role in volume 2, you just have poor reading comprehension. I specifically mentioned that as one of volume 2's flaws, I just don't think it makes volume 2 a winner for worst written volume unlike some melodramatic speedreaders letting shitposters and memes clod their judgment.