Despite being nemesis, He Juan had to begrudgingly acknowledge that he knew Ku Jin's temperament quite well, and vice versa.
He was the type of person who acted based on only two reasons: personal interest and Luo Xuan's commands. Last time, Ku Jin had played a psychological game on him and stressed him out for two weeks because of personal interest. How about this time? Because oh, he was so certain that Ku Jin was involved in the ongoing chaos. He couldn't have mistaken this suffocating sensation as if he had stepped onto a deadly quicksand, one which would only drag him down faster the more he struggled. This was Ku Jin's style of action.