and that could be one reason why the killing stopped.
No ammo left.
(b) Jammed firing pin in the gun and no way to fix it. No skill to fix it.
(c) A distaste for getting up close , at first , to a potential victim, .. in other words, an avoidance of violent contact with people who may fight back, even perhaps win. The remarkable absence of any obvious signs of altercation on both Kam and Bryer in the store video, no bruises, no scratches , no limping, no black eye, and let's keep in mind, that when we see that video clip they have murdered three (3) people, all of whom loved life and were living it to the full and had no intention of folding. All healthy and remarkably fit and spry.
It seemed obvious to me that they had disabled their victims first, by gunshot, perhaps, certainly by surprise, with no advantage given , or mercy. Then the killing processed at the pace they set themselves. That did not include any chance of them receiving any injury at all.
So when they couldn't do the killing their way, it probably stopped.
They do have encounters people, up close ones, but without their weaponry that enables them to keep a distance between them and their target, it may not have seen to be a comfortable thing to do. No point , if one's target is going to go you, with all the fury in the world.
The girl at the little shop was alone. She was in a remote place. They could have just walked back in with their weapon and kill her the way they wanted. I am sure they saw plenty of people alone on their trip. I am sure they didn't lack of opportunities to kill if they wanted to. JMO
I am tehre is any evidence known at the moment to conclude the killings happened the way you describe it. It could have been panicky and fast JMO