Can arousal occur during ra**? Yes. A number of people who report ra** experience arousal/org*** but this does not mean they were not assaulted. Org*** is a natural biological response to a simulation, it is somewhat like being tickled, no matter you want it or not you will laugh. As humans, our body has an involuntary response to stimuli, therefore even when you are being assaulted and its awful and quite violating your nerve endings still respond to touch.
It's infuriating seeing these people here speaking on ra** when they don't know anything. Stop the victim blaming! Taekyung is clearly victim of repeated ra** and there's nothing NOT traumatising about it.
most readers glossed over the fact that taekyung was raped multiple times during the first season already by heeseo because "he enjoyed it" and it seems like those readers haven't changed even with the new season but oh well i shouldn't have expected for anyone to change when they have been like that always. Ra** is not okay and as you already explained, sadly victims do get aroused against their will but it doesn't make it any less worse, it's still ra** and it's horrible. A lot of ra** victims also start feeling shame and blaming themselves for getting aroused even tho it's just a bodily response. Ra** fu*** with their bodies and mind. It's just all over fuc*** up.