Until now it seems that Jiwook and especially Joohoon are responsible for the death of Siwon. The relationships i ship are jail×Joonhoon and misery×Jiwook till death do them apart. I do not care if it looks hot to other people to me is sick since jiwook is very AFRAID of that bastard. But that is different opinions, just hoping that the yaoi god won't hear your pray! ┑(￣Д ￣)┍
I always thought Siwon died because he switched bodies with Taemin? All we know is that he was raped because it was either going to be him or Jiwook, which I'm not saying justifies anything if correct, just that we don't know the whole story yet. I'm also not saying they're good people, just interesting characters. And it's not really that they just look hot together but I think their relationship had potential, but unfortunately by Jiwook's reaction to Joohoon calling him it looks like it did not live up to it.
AHHHH dammit I didn't think I would ship it this damn hard. I still don't like Jiwook that much and Joohoon was pretty annoying in the previous chapters but I dig their chemistry so far, this flashback is pretty interesting. Tho it doesn't look like their "relationship" was any good *sigh*