Yet another example of "its better to be lucky than good". Considering the haphazard shot placement resulted in two out of five rounds being lethal hits at melee range, and one of those two being a "sweet spot" hit resulting in significant trauma to the CNS, the two most significant points of interest are that he was only able to get off the same number of rounds as he would've with a revolver, and one of the five rounds resulted in a self inflicted wound. You can harvest a polar bear with a 22 rimfire if you can reliably place your shot and you know where to put the round.

Spray and pray is never a good tactic against any opponent.

I know a few bear guides in Alaska, and none of them consider any handgun round an effective defense against brown, griz, or polar bears. 12 gauge pump with slugs seems to be the most popular firearm choice for defense against bears. Appropriate bear spray would be preferable.