When a round is in the chamber has nothing to do with this or any other act of negligence.
Sure it does because people are human and people make mistakes. "The rules" are redundant and in a fatal incident almost always multiple rules are broken. Without even getting into the hot/cold chamber debate
when hunting, one of the "rules" more people should pay attention to is, don't load your rifle when you're not hunting and there's no reason to have a round in the chamber. Like before legal shooting hours, in or around a vehicle, and so on.
Sure, you can say that if he'd kept the muzzle pointed in a safe direction nothing bad would've happened. But you can say the same about not loading the rifle until there's a reason to.
