Maka911,892,828 Locked 24 Oct 2012
During the Mission "Rip Current" you will come to a part where you are put into a boat with a grenade launcher for exfiltration. At this point you must kill 20 total enemies before you get to the end of the mission. Just use LT to aim, and RT to fire, killing as many people as possible. If you come to the part where the boat starts reversing to avoid damage and have not unlocked the achievement, just restart the checkpoint.
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