Very nice.
Maybe try to lure them into rooms you can lock before killing them so when they respawn you can loot in peace- if there is any loot.
Kill through windows of locked building?
Break their arms?
Can turrets be deactivated so they are not dead/can't respawn?
Have a few dog handlers to release decoys/use up enemy AP so you can close in/kill?
Jus' Thinkin'.