Protip for people wanting help. 1 planting the zombie shield near the machine will help, he will generally to for that, you can run away and he will attack the machine after. I needed to do this for deadshot and speed cola myself. 2. You can't be too close to the machine, you can lure him to the area but you have to be far enough away to take his attention away from the device. He seems to love taking down windows, workbenches, and the mystery box, but you need to be further away from the perk machines though.