Funny story, I almost killed myself the same way. I was on a ladder removing a flexible steel hvac hanger from around a 6 inch vent. I reached above my head and unscrewed one side and let it hang down. I needed two hands to hold the drill and other end of the hanger. As I began to unscrew the other side the loose end swung around pretty quickly from the torque of the drill. The loose end struck my neck right at the carotid and jugular. I had a deep enough cut I needed a bandaid. This was right around the time Final Destination came out so I was thinking something else was going to happen to me soon.