i need an explanation why did ilay get so mad after taeui cried when they were interrupted...

He feel bad seeing him cry cuz tae was really sad and hurt, then got angry cuz he was feeling bad, he already said that his brain and heart want different things (one is kill tae so he dont feels confused anymore)

It is something like that, yeah. Ilay is someone who doesn't know what to love or to worry about someone is. He knows only killing, no empathy and getting what he wants no matter what. As Tay appears in his life he slowly starts to change and have feelings which he never did before. Ilay is confused. When he saw how hurt and crying Tay was, for sure it hurt him too and one of the reasons is because the source of that hurt is him but since this feeling is unknown to him he got angry (I think on himself). Also he got angry too when he assumed that Tay doesn't like him or doesn't like doing the things with him (as we saw of Tay's thoughts he actually likes it more or less) That assumption hurt him and that's why he became violent and persistent with Tay "to teach him a lesson". I don't think Ilay still understands himself and all this is very confusing for him. That's why he lashes out but the next chapter is gonna be interesting on Ilay's behavior :)

I also think Ilay is not used to feelings and emotions, and being with Taeui has him feeling all sorts of emotion so he doesn't know how to react. I think that's why he gets in foul moods when Tay says something that he doesn't like, but Tay also doesnt realize that what he is saying is making Ilay react, because to him Ilay does not care about people

I think that's very on the spot (๑•ㅂ•)و✧

Thank you everyone who explained it