I unloaded my firearm, checked it clear, removed the firing pin and spring, and then tried to figure out how it would be possible to do anything with the weapon that involved reloading it while having a hand in a position that could get hit by a bullet leaving the muzzle while reloading...
I can't seem to figure it out... I would need 3 hands - was his friend helping him reload while they were walking, or is there more to this story?
It may have happened while he was holstering up after reloading. Lots of inexperienced shooters or people who use those floppy holsters wind up using two hands to wriggle the gun into the holster, in spite of the fact that this is practically impossible to do without muzzling your support hand.