Maggie's Farm

Phil must have some tradecraft in his background.

A well establish way to create a killing field is to do exactly what he described.
One could even throw a simple smoke grenade inside a store. Where are the people going....out the door..where do you kill them..outside.
Create any diversion to get the herd moving in the direction of the door they came in, which is what happens 99% of the time...

One should ALWAYS locate an alternate escape route, usually through the kitchen which always has a delivery door or out a bathroom window if one is available.

Sad stuff to contemplate but that's our world right now.