The real issue is that this man grabbed a .243 to kill a large grizzly. Must have had a couple of good shots on it to stop the charge with the second shot. That made the third shot necessary for an ethical killing of a wounded animal. .243 is much more a varmint rifle than a grizzly rifle especially with the .55 gr bullets that tops out at about 100 gr bullets. That is not much to use against a large grizzly.
If I lived in that neck of the woods, I would have more than a .243 ready to go. Well, it is only a couple hours north of me right now, but having a better option might have kept the entire third shot from being an issue. Grab enough rifle to get the job done with one shot.