equip your syringe in your items menu kill him then grab him from behind as he gts up and stab him in the neck with a syringe

I HAD SAME PROBLEM WITH MY INTERCOOLER. (3 RED LIGHTS) COME TO FIND OUT THE POWER CORD WASNT ALL THE WAY PLUGGED IN. SO I LAYED THE SYSTEM HORIZONTALLY AND MADE SURE THE PLUG WAS IN TIGHT AND IVE HAD NO PROBLEMS SINCE. AND MY 360 STAYS WAY COOLER THAN IT DID BEFORE THE INTERCOOLER.