During the mission "Numa Numa Trial" you will play as Wade who as am ability where you can press
on the D-Pad to see enemy outlines through walls, if you ADS with your weapon while there is an enemy in front of you, you will "snap" to that target allowing you to easily kill it. If you kill and enemy, it will "snap" to the closest and keep going until the ability wears off
Best place to do this is near the end of the mission when you are on top of the plane being pushed out the hangar and down the runway. You will be given a LMG that has unlimited ammo and a bottomless clip and there a loads of enemies around to kill.