Can be done mostly anywhere. Abilties like Camoflauge or a default swarm or stuns can assist. You can do this on every mission but an easy place is on mission: Rise & Fall. Once you are in the area where you get the "Spike Launcher". Head up to the very back right of the map, you will see a building, next to this is a large metal wall with a hole in it. This is the only AI spawn at this current time. 3-9 enemies spawn.