Splitting the house in two, he shouted inside at the mortals, "Run if you don't want to die." Alternatively, he could use illusion techniques or suggestion techniques to drive away the crowd.
Calculating potential routes for the crowd, he then eliminated every Ancient Method Practitioner on those paths, either by suggestion or by deliberately destroying buildings to block some paths, reducing variables.
As for property loss, Wang Qi had automatically ignored it. Under the dual premises of the Immortal and Mortal, a slight leakage from the cultivators' fingertips was enough for mortals to fill their bellies, not to mention the wealthy Immortal Alliance. Eventually, the mortals would report any losses, and the Immortal Alliance would compensate accordingly—as long as the numbers weren't too outrageous, the Immortal Alliance wouldn't bother to verify.