GHOST 1.0

The earlier you try to do this achievement, the easier. But it's easy at endgame too lol. It can be done on any alarm so just stay crouched on a low level alarm, you can take damage and everything just don't move and try not to die. I didn't had time to test because I unlocked it too fast but maybe you can roll while crouched. In later game, you can unlock the "We Are Legion" from Jacker's Row in the skills tree and he'll send friend robots to help you, depending on the alarm you don't even have to shoot, just sit there and watch. Also, the last Primary Weapon you get makes this achievement easy even on Hard Survival @ Alarm 20. Just crouch, shoot everywhere and the achievement unlocks.