Wang Kai'an chose to back down because the incident was actually Chu Nan's doing; he had no need to take the blame for Chu Nan.
"You think you can run?" As Wang Kai'an made to leave, Sun Haoyi immediately panicked. With the situation stalled here, if this guy got away, would he still go after Chu Nan or not? Therefore, he could only continue to target Wang Kai'an, "If you don't apologize to Young Master Sun today, don't even think about leaving here alive!"
After speaking, Sun Haoyi grabbed hold of Wang Kai'an's clothes, preventing him from leaving.
However, this action completely ignited Wang Kai'an's rage. The pent-up fury in his chest surged to his brain, and without thinking, he spun around and delivered a textbook roundhouse kick, "What the hell do you think you are? Daring to confront me! I've been tolerating you for a long time!"