Why did Qi Ming commit suicide after Yi Yao jumped off a building?

In the movie Regret for the Past, Qi Ming seems to have just moved out of the place where Yi Yao grew up, but in the novel, he died of gas poisoning and committed suicide. I think the reason is determined by what he has experienced.

Yi Yao in the novel jumped to his death, and was cornered by the world, even the last ray of light was obliterated. She chose to face the pain brought by school bullying with death. In Yi Yao's life, Qiming is her light, but this last glimmer of hope, because Gu Senxiang's death has disappeared, she can no longer live in pain, so she can only end in death.

But for Qi Ming, he is an excellent student in everyone's eyes. He is gentle as a gentleman, but he is also the only one who doesn't know why Yi Yao resisted after being bullied by others. The only person who protected Yi Yao but misunderstood Yi Yao felt that he had cut off Yi Yao's last hope.

After Gu Senxiang died, he left in front of the person he liked. The murderer may still be Yi Yao, who grew up together and had deep feelings. His hatred for Yi Yao kept him alive. He has always misunderstood and wronged Yi Yao. But when he witnessed Yi Yao's suicide, when he realized that he had been wrong all along, he even lost his faith in life. He thinks that the world is not so dark, but in fact it is because he has been in the light; He thought that others had changed, but in fact he could not see the insults and injuries suffered by Yi Yao; He thinks he is right, but he is always wrong.

Qi no longer lives alone in such a world. In his later years, he will definitely have a debt and guilt to Yi Yao, a denial to the world and himself, and more thoughts about Gu Senxiang. All these became the reasons for his suicide. Of course, this is just my personal opinion.