Cheat Mode...
	Enemy versus enemy...

Press ~ during game play to display the console window. Then, enter one of the following codes and press [Enter] to activate the corresponding cheat function.

Effect	Code
999 ammo for all weapons	allammo
Add weapon or item to the world	summon [item name]
CA Rifle (press 3 to switch back)	Summon CARifle
Disable flight and no clipping modes	walk
Flight mode	fly
Grenade launcher (press 4 to switch back)	Summon Grenadelauncher
Invincibility	god
Invisibility	invisible
Jump to indicated map	open [map name]
Jump to indicated map with current weapons, items, dispersion pistol upgrades	switchcooplevel [map name]
Kill all of indicated enemy type	killall [enemy name]
Kill monsters	killpawns
No clipping mode	ghost
Normal view	behindview 0
Reset graphics and textures	flush
Rocket launcher (press 5 to switch back)	Summon Rocketlauncher
Set game speed	slomo [number]
Third person view	behindview 1
Toggle time	playersonly

To get two of your enemies to fight, get behind one so that the other hits or shoots the first one. Then, step back and they will start fighting each other. They will fight until one kills the other, then it will turn its attention back on you.