Hyeso is just being dumb at this point. In my opinion he just need to accept that haeil is half human and half orca and might have or gonna have some violence tendencies. Like duh, what do you except of someone who is been abandoned and locked up in a tank and dark place and everyone around you is seeing you as an
Animal. ? No Shit he is gonna be violent at some point, and also with his personality type he ALREADY have that in him. So just accept it, find out about his past and help him do right again. It’s like me acting shocked on why like those famous serial killers are killing people. It’s either something wrong with their brain when little or they got that point because of how other people treat them or both. It’s nothing to be shocked about.
For those that are mad about Hyeso being upset --> pls remember that one of the lurking, underlying issues is Haeil's identity, whether he is more human or more animal, how his genetics and his role in this world of science will be significant.
Hyeso constantly has inner turmoil about morals and being a good person, which is why he constantly questions the ML's identity as being either animal or human. Haeil himself is more Orca but has a desire to be human. And then finally, we see that the antagonist has some greater plans for Haeil and also looks STRIKINGLY SIMILAR to Haeil. It may hint that Haeil actually started human.
In summary, this identity crisis is pivotal to the story and is why Hyeso gets upset. He's not really sure how to categorize Haeil, thus he's not really sure whether to hold him accountable to human standards or not. If he's more animal, then it raises the issue of whether their love is truly mutual, but it also gives him more leeway to 'mess up'. If he's more human, then their love would be the same, but it would also mean that the Haeil is more conscious of his wrongdoings(lying, violence)
Here, both chars had JUST painstakingly confessed their love. For Hyeso, this is an acknowledgment that theyre on the same playing ground. So to follow up with finding out his lies and violence, its jarring. On top of that, Hyeso is mainly upset that Haeil lied about hurting the SA-er, however Haeil has also hurt others too, like the crazy guy. Haeil was violent towards the man and stole his clothes, despite the man being otherwise harmless.