Responses
Looks to be heading that way. Based on this and the raws, I would speculate Jinhan kind of took for granted Hyeongjo’s feelings for him; thinking that Hyeongjo would always be there for him or even basking in Hyeongjo’s adoration in a sadistic kind of way, feeling superior about it and he really never thought that Hyeongjo would fall for someone other than him. Now that he's realizing there's something going on between Minjae and Hyeongjo, he's getting kind of a wake up call, feeling anxious about it.
Okay so Hyung likes Hyeongjo and is prolly using the other blonde student as replacement because his younger childhood friend is not making his move yet despite Hyung knowing Hyeonŕgjo has a thing for him for the longest time. And now, he's brokenhearted because Minjae, whom he used to make Hyeongjo jealous so we would confess, ended up 'stealing' the love of his life? Is that it?