They aren't even necessarily intending to kill. Shooting center mass in a panicked situation against a moving target has the highest likelihood of landing a hit due to center mass being the largest area. There also happens to be a ton of important organs there. You could try to aim for a leg or arm to be non lethal, but if you miss several shots the intruder could close the distance and harm/kill you.

You can kill someone during self defense and still have it not be intentful murder. Some people take 6 rounds to the chest and can walk away from the hospital, some die to 1 shot. An intruder can break their neck and die after falling during a physical struggle, is it fair to say the defender intended to murder them?