
That's what I came figure out and is making me crazy! And the shaking mirrors, other people could see them so it's not just these two. So the creepy reflections must be real too?
I think whatever is in the mirror came out (the exploding glass) and is somehow killing people? Or sucking them into the mirror. So it's a literal split personality, the evil reflection gremlin is the one killing people.

but a lot of people witnessed that? while tae jun was walking down the streets and somebody exploded in front of him and all that was left was blood everyone saw that. even in the cinema it was the same thing. both were public places... so i don’t think that was a mere hallucination. it’s not just psychological there’s also something supernatural in this case

YESSS the professor could see the hands which is also something that tae jun could see, so i don’t think it’s entirely psychological at all. it’s not like they discussed that with each other so how would the professor be able to see the same thing as tae jun if it’s only psychological?
there’s definitely something supernatural in that house lol esp in that mirror and the key to finding that out is inside that room
For me, there is nothing in the dark room. I think there are just memories of Jun. I also think Jun has multiple personalities and it was he who killed the parents with the help of Yeon Woo.
I also think Yeonwoo has become like this because of Jun.