While I'm sure there are many good location for this achievement, I'll tell you the place I just unlocked it. During the mission "Destroy the Bomb Caches" you will be in the Shrouded Clans hideout. After you blow up the first set of bombs, take the elevator down. Leave the elevator and quietly dispose of the lone guy here. Then as you proceed carefully ahead you'll find a large room with 4 more guys in it. Launch your bot and simply provide it cover as it brings you at least 3 kills, and this achievement.