Although Chu Yunfan was not a professional poison master, he was able to determine a poison's power based on the knowledge he had gained from the Alchemy Emperor's memories.
Zuo Wenbin was pretending that he had lost the ability to move to ambush Chu Yunfan. But it was impossible for Chu Yunfan to fall for such a trick. Instead, Chu Yunfan immediately realized the situation and stalled for time to allow the poison in Zuo Wenbin's body to deepen.
The two of them schemed against each other. The fight had begun long before they even made their move. Chu Yunfan could not help but sigh at Zuo Wenbin's shrewdness. Even while being ambushed, Zuo Wenbin was still able to calmly think of a countermeasure. Chu Yunfan was able to gain the upper hand in this psychological battle purely because he knew the outcome beforehand. Zuo Wenbin's plan was destined to fail.