You can use any combination of weapons.
You must be fighting a team of at least 4 people.
You must get an overkill which is killing 4 people within 4 seconds of each other.
But you must get the overkill of all four.
ex. You must kill person 1, 2, 3, and 4 on the other team. You cannot kill person 1 four times or person 2 two times and person 3 two times. You must kill all members of the team with an overkill to get extermination. If you did do any combination of killing, like mentioned above, you still get an overkill, but not an extermination.
-I recommend playing a game with 4 people per team such as swat, snipers, or team slayer.
I mostly recommend swat because if you are good with the BR, you can one hit KO headshot the 4 members of the team easily. That's where I got my extermination.
