Sumin and Garam

I agree. There was more warmth between Sumin and Garam's character, but was sort of left off by the director. And he since he didn't know what to do with him, he killed him in a car accident. So, issue is solved, and he could focus again on Sumin and Jaemin's relationship which, I believe, could have been built stronger in the story, and should have climaxed at the end, but sadly it became a horror/suspense movie, and the characters weren't really able to build on the emotional side, but rather became sort of a horror and a joke. Disappointed with the ending!

Sumin clearly was not into Garam romantically. His kindness to Garam, beyond his general kindness, was motivated by the fact that Garam looked like someone whom he liked back at the orphanage. That's why, when Garam asks Sumin why the latter is so nice to him Sumin says Garam resembles someone and doesn't clarify whom Garam resembles even when asked. Also, prior to Garam's confession of his affection for Sumin, Garam drops hints that Sumin catches but chooses not to acknowledge, such as the one by the riverbank. Sumin brushes aside Garam's attempts to check out Sumin's receptiveness, even going so far as to reframe the brush-off in terms of work (that Madam doesn't like homos working for him). Sumin's interest in Garam is purely brotherly as a hyung looking out for a younger version of himself.