Wow, what a crazy episode. 

The interactions between Soo Chang and Dong Tak was too much! When Dong Tak started stripping in public... i'm dying. 

At the end, when we see the flashback, there are two boys. I believe the one in the car accident is Soo Chang, and the kid that saved him was detective Hang Joon (the dead cop), since he was wearing the necklace Dong Tak is now wearing (though it could also be Dong Tak..?). This would explain Hang Joon and Soo Chang's relationship more, and possibly why Soo Chang and Dong Tak are connected.

I am interested in how Soo Chang knows the motorcycle guy though...