Why is Zuo Qing's resignation the last time he mourns the emperor?

This is Zuo Qing's fake mourning for the emperor.

Zuo Qing's speech was poisoned by death, because saving Su Xuan was poisoned again, and he was left with the rest of his life. Later, he planned to bring down Wei Minghou and let himself speed up the poisoning. The remaining life is only three days.

In court, Su Yun stabbed Zuo Qing with an inch of acacia and killed Wei Minghou. Wei Minghou's body, Kang Jianzhi people still died on the spot. Zuo Qing's resignation is extremely slim, and his chances of survival are almost zero, if he can pass his chest.

Even if this knife doesn't kill Zuo Qingci, the poison produced by his death is incurable. When Zuo Qing decided to pretend to mourn the emperor, he was determined to die because he knew that he would die of poison sooner or later.

Plot:

One-inch Acacia for Teenagers is a martial arts romance film in ancient costume, directed by Mao Kunyu, starring Gala and Zhang Yaqin, starring Zou Tingwei, Deng Yuli, Zheng Hao, Shi Yunpeng and Xu Mengyuan, starring Huang Haibing, Lu Xingyu, Chunyushan, Zhang Zhengyang and Ren Yu, and starring Gu Kejia, Qiangyu and Yue Xin.

The play is adapted from Wei Zi's short story An Inch of Acacia. It tells the story that Zuo Qing, a "young hermit", searched for the lost imperial treasure "The Map of Mountains and Rivers" as a quack, thus getting to know the thief "Fei Kouer" in Yi Rong, and then they dug up a secret history of Jianghu together.