chanil found his gf with someone else late at night and when he confronts cirrus, he didn't clear the misunderstanding. rinrin and chanil was set up by cirrus, they might have real feelings for each other but for chanil who found out that cirrus set him up with rinrin because of other intentions, he must have felt that cirrus and rinrin was playing with him, that rinrin's feelings might not be real. rinrin might have also thought that chanil might not believe her. the slap might have been unnecessary but she's a teen and not all teens have the composure to get up and leave when they feel hurt/mad/betrayed.
I understand your point. Unfortunately, after seeing the raws, it justmakes this whole issue with these lovers and Cirrus makes it unfair to Cirrus alone. Makes one wonder if its really easier to let go of a friendship for a new lover. Or maybe i just felt like rin didnt show a bit of empathy towards her supposed to be bestfriend after hearing everything while also knowing that he's in the dark (her knowing full well how Cirrus acts when he's jn the dark). But you're right, they're teenagers. Most of us of that time are caught up in our own hardships we fail to recognize other's situations. Hope they grow out of this, especially Cirrus.
She agreed to being set up but she didn’t know he set her up to make skylar jealous/sad that day, and thus use her unknowingly. Just as well, I think Cirrus started the conversation trying to push her away preemptively rather than being rejected, and so confessing he deliberately mislead Chanil because he himself felt jealous and didn’t think about her at all, while he hasn’t talked with her of any of his other problems aside from Candy’s situation, might have make her push back like that. She shouldn’t have slapped him and if she thought a bit more about all of it (and had more information honestly), she might have reacted differently, but she’s allowed to feel hurt and as a teenager she doesn’t necessarily have to have the full emotional intelligence to compartmentalise her feelings and react graciously first.
if someone used me for their hidden intentions i'd be mad and upset too. especially if they're someone i'm close with and whom i trusted.