Well, the problem is that Seungho won't give him a fucking chance to explain anything, and he doesn't believe any of Nakyum's words at all. Seungho only hears what he wants to hear. If Seungho thinks he ran away, then that's that, unless he hears it from Nakyum mouth or some concrete evidence, that he was kidnapped or if he was doing something else, he won't believe anything.
You have to remember na kyum is traumatized. I mean it's like when someone in real life gets kidnapped and they manage to escape or are released but they won't tell the police who kidnapped them because the kidnapper threatened them. It's easy for us as outsiders to say "oh come on just tell them already, you are safe" but for someone who just went through something traumatizing it's probably not so easy. Who knows what is going on in their minds. Also Seungho is not even giving na kyum the time of day, he is automatically just treating him like shit. He could have picked up on na kyum's body language and been like hmmm he seems hesitant... something is not adding up.
I'm not talking about him not saying that he was kidnapped. Everyone reacts differently to a bad situation. My example was something that I would do if I was in his situation. I Should've gave more consensus to that in my reply earlier. There was a time in the story where he could've picked better word choices than he did and that lead Seugnho to be mislead by his words. Nakyum is being treated wrong and he's getting raped by Seungho a lot and thats bad. I just feel like Nakyum isn't 100% perfect because seungho influnced some of his actions that made the situation worst.
I get it seungho is a bad person but literally nakyum isn't in the right either. He could've told him that he was sleeping and he was taken to a random place and that he didn't know what happened. He could've informed him about it without telling too much. Also don't get me started with the whole "We're just two bodies" thing. I don't know who to like because Nakyum set this on himself and Seungho is just too much.