Knowing Taemin, he's not going to be affected as the victim of the assault, but he's probably going to avenge "Siwon" by beating the shit out of the perpetrators; that's exactly what Siwoon/Woo-Jin is probably betting on and why he let him cancel their study time so easily. Taemin's sense of righteousness is not going to allow him to stay still after watching the contents of that video. He's heading to the place indicated in the note without hesitation.
But the one that left the CD was siwoon, no? It was his idea to show him the rape tape.
Yes, it was Siwoon who arranged it. He wants to see Siwon's reaction, if he reacts like "Tae-min" would react.
Duhhh!!! He's strong so i hope he can brush it off like" I've seen it in my dream why r u showing me this?" in his own badass way. I don't want him to meet more hardships!!! T^T
But this is a manwha. ╮(￣▽￣)╭