I thought this might happen the moment she kept holding the knife and said she wanted alone time with Misaki! I kept thinking ”Uh-oh, girls, should you really be isolating Misaki for her..?”
well tbf they DID mention that if hareta got enough affection points with her but end up picking a different girl, she'll stab him - honestly I've been expecting this exact scenario since the moment misaki finally relented, I'm just surprised it took this long.