Start up mission 4 and walk around past the reception and continue down the walkway you'll come across an Android with he's back to you slowly walk up to him and use
twice and then turn and run away back to the start thus losing him. Once back at the start start making your way back to him and creep up on him and do the same as before then return back to the start and do this one final time and he will die netting you the achievement.
Just be very careful after you return to him because if you run or walk up to him he probably will turn around and chase you.
Maka91 offered me he's video to show how its done so thank him.