Currently there is a glitch that locks this achievement if you kill any civilians at all.
In order to unlock the achievement you need to delete your save and close the game before restarting and completing the requirements again, making sure not to accidentally kill civilians.
Speeding through the first two missions should take under 30 minutes with the second mission unlocking the achievement.
Use your penumbra vison
to locate civilians, they will be glowing yellow, then try to sabotage as many enemy spawn points as possible to reduce the enemy health, then do all your fighting away from the civilians.