Who's backing him up?

There’s a big name backing Moon Sik without doubt but the question is who is he; I have strong suspicions about the chief police and I am almost sure that he’s the one. Also, I always thought that Moon Shik didn’t want to kill Hyung Joon and it turns out to be that way; he shot him thinking that he was wearing the bulletproof vest but Shi On took it off for him. The rest of the episode was so freaking meaningless and stupid, actually except the last few minutes, I don’t know what’ the point of this episode.

Seriously?!

He didn't see he wasn't wearing the vest? He obviously changed his clothes...why did he not doubt for a minute that he might not be wearing one? Wasn't the wearing it over his shirt the last time he saw him?