with the perfect profile shot presented, a shot to the hip girdle would have not only stopped the assault, but would have likely prevented the need for a 2nd shot...it gets his attention and disrupts the skeletal structure enough to prevent rising again, while at the same time avoiding the immediately mortal shot the father was trying to avoid
In the Marines they taught us that a shot to the pelvis is incapacitating. Mobility kill. Hit the pelvis bone and he'll stop coming at you.