But you said he wouldn't have left June when she'd been shot, or he would have checked the other occupants, so do you think that he left his severely injured wife in the hands of a killer? If she hadn't been shot at the point he left the room, do you think he would have left her to her fate?
If you think he fled before he realised there were no bullets left, he would have had to just abandon them all.
I don't think there was any thought, just an instinct to get away.
If he had been given time to think and react, by the killer leaving, then I think he would have checked on others.
Obviously I do not 'know' this, but that is my view.