Strength in numbersG 10

Strength in numbers G10:
Got a full squad in the last zombie map.

In order to unlock the last zombie map (The Marching Dead in Operation 4: Blizzard), you either need to complete all 7 missions on 3-bullet difficulty, or pay 5 medals. You don't need to complete the 4th operation for any achievements, so whichever way you want to unlock it is up to you. A full squad is four troopers. I unlocked the 4th on wave 10. You need to actually run to the squaddie for the achievement to pop. I didn't let anyone die up to that point, and I'm assuming you have to have all four alive for it to count.