No Assistance Required Achievement
No Assistance Required20
Complete a Special Ops Mission Mode game on Hardened or Veteran with no player getting downed.
The best and easiest map to do this is on is "Milehigh Jack". As it's quite short and not much room for the enemy AI to maneuver, it's the perfect place. I'd start out on a lower difficulty to get where people spawn, and what's best when.
Just be on your toes, and using your flashbangs is a must. The only hiccup in this level is the timer, but once you know what you're doing, it's a breeze. For more helpful info on some Veteran tactics please see the "The Best of the Best" achievement up top.