She has a bruise on her arm -> Maybe the guy who just helped me is beating her -> He's definitely beating her -> Let's get him away from her without explaining or discussing it with anybody.
Nope, don't forget about the abusive piece of shit/sexual offenders. Remember her ex and the photographer? Seriously though, he found out that MC lives together with his daughter, saw one, single bruise on her arm and immediately decided that he's abusing her? Did he already forget about how gentle he was before when he was helping him? He truly is braindead.
Ok it's the same jump to conclusions but wrong scenario but the dad has sort of gained my respect for speaking up to Sugawa about the misunderstanding he made up