This achievement is called watch out for the little guys.
Reply to my own post a friend help me get this achievement. Now I need one more (Living Legend).
I had a field day with this one. Which level was it that you needed to get this achievement?
That’s the one about not killing any grunts right? Just use a dummy controller.
Now the really impossible achievements for CEA are the 2 ones for the library. Beating the library on legendary in 30 minutes or less and beating it on heroic or legendary without dying. Those 2 are -Yoinking!- impossible.