In Dayan, although using a Qi Machine Lock on someone hadn't been made illegal, its nature was akin to shoving a loaded gun into someone's mouth.
As a guard, could you stand by idly if you saw a gun pointed at your master's throat?
Certainly not.
It didn't matter whether it was Qin Weishu's carriage driver or people like Guest Elders from the Prime Minister's Mansion such as Zhou Chen and Ying'er, the reaction would be the same.
When guards made mistakes, under normal circumstances they were expected to die alongside their masters.
And that was the trap.
Xu Mengxi used the Qi Machine Lock on you, and you could certainly lock her back, but if you struck to disperse this stream of Qi, it would be considered attacking a government officer.
If it had been Xu Yuan in Qin Weishu's position, he would most likely have advised her with a word, and it would have been Xu Mengxi who couldn't extricate herself from the situation.
However, these were all his insights from experience.