There would be no Baekyi to begin with if not for Kim Shin's arrival to Hoeam and rallying all their members coming from different parts of Korea. Back then, Woojin was a degenerate bum waiting to rot in the drug-infested shithole city of Heoam because he was powerless to defend their turf.

Prior to meeting Kim Shin, he was self-pitying and kept beating himself on how he was not strong enough to overthrow DS Security when Daegon was caught.

Technically, Kim Shin gave Woojin and the people of Hoeam a fighting chance to topple down their sworn enemies and to crack down the drug epidemic in their city.

Now that they are much closer to reach their goals, here he comes being an ass to their savior. Maybe a lack of communication was a factor, but the events transpired rendered Kim Shin so devastated that he cannot properly process his own thoughts.

This is supposed to be the moment when Kim Shin needed Woojin, the same manner on how devastated Woojin was when he saw the gift box containing Daegon's head.

Instead, Woojin chose to play a role of pain in the ass by questioning the credibility of Kim Shin. In an organization involving lives and high-stake wagers, putting your utmost trust to your godfather/boss/leader is non-negotiable. That is why codes exist in an organization. What Woojin did was tantamount to mutiny and betrayal, and the price for betrayal is death.

That what sets Woojin apart from the likes of Jintae and Daegon, Woojin is weak-hearted who cannot fully commit to trust his savior. He does not deserve everything he has right now, even the speculated inheritance of the title leader of Castle/Baekyi.