c) Continued to pursue long after the threat had been eliminated
Point C is arguable (and I'm sure the jury will do just that). There are no excuses for points A and B. None.
Someone breaks into my house, they're going to get shot if it's up to me. Fear/panic/anger would probably drive me to pull the trigger instinctively, too, based on how I think I would feel in that situation, but this fellow went far beyond that.