Walter Attacked By David?

If you see the shot in the trailer you "clearly" can see an outline at the right side of the frame of someone. Maybe David. A over-the-shoulder-shot. That person is using his left arm to thrust this thing into Walters neck, below the ear. Probably a bad place for an android. But if you look again in the shot, on repeat you see there is a person standing in front of Walter. 

If you see the shot in the trailer you "clearly" can see an outline at the right side of the frame of someone. Maybe David. A over-the-shoulder-shot. That person is using his left arm to thrust this thing into Walters neck, below the ear. Probably a bad place for an android. But if you look again in the shot, on repeat you see there is a person standing in front of Walter.