Right! Look at his actions prior to him killing himself. went to his coaches and thanked them. Obviously on a mission and the gun only offered convenience. If he didn't have it, no question he would have found another way.
and shooting his girlfriend 9 times was probably emptying the gun. Such rage would have found a knife, if he didn't have that gun.
An even better chance of only one dead is if SHE had a gun in self-defense and was very proficient with it.