This one is a missable achievement that takes place on a very specific mission: your first one, on Groom Range. Toward the end of the mission,
The Skyranger will swing back to pick you and your crew up, and you must defend the area during that time. If there are any Outsiders left, including drop pods, before you board the Skyranger, you will not earn the achievements. Be careful,
Begin your defense by having Kinney and Nils focus on the Outsiders while you hammer on the drop pods. Kinney's abilities are great for crowd control, and Nils can use Critial Strike on drop pods if you're having a hard time taking them all out. Once the dust settles, play clean up by opening battle focus, and using the controls to cycle through all available targets. If there are no remaining targets, board the Skyranger and enjoy your new achievement.