...despite what anyone thinks, I believe that what Jonwoo did it's for the best. If he stayed, he in his low self-steem would only remember the ugly things that happened and would never move on.
Sometimes you need to be alone, it and have some time alone to rebuld. Yes, it's harsh. Running and fleeing is cowardly and selfish when you may have people that worries about you, like Hamin, Yuri and maybe Taeyang, but sometimes you need exactly that. Once you've calmed and though things proper, then you can rebuild.
I know all that because once I was not that different from Jonwoo. I pretty much know what he's going through and it's not pretty, but you get out of it. The question is how many of the people he knows will be at the other side.