@Starship2020202 For Baek, Cheng is relatively harder to deal with. If it were just an ordinary whistleblower, they might have been silenced or even eliminated. That's why Baek used her friend’s life to force Shin-jae to become that person.
@Starship2020202 Baek needs the marriage. He and Kang’s mother Cheng are of the same kind: they don’t directly participate in wrongdoing, but they indirectly help those who do in order to achieve their own goals. The video evidence has just taken down some of the VIPs. How about others?