And I'd further surmise the slugs were solids, not hollow-points.
I’m guessing those were 3 shots at point blank range fueled by adrenaline. Well-placed? Perhaps. Inside a tent it would be a point and shoot situation Solids vs hollow points? Who knows. JHP/JSP’s are certainly more common than solids and these were likely commercial loads purchased in Europe so more likely jacketed bullets. At contact range it wouldn’t make much difference.
This was a two-year old bear, IOW a teenager who would not be fully grown. Teen bears - just like teen humans - are always the most trouble.
Tent camping around polar bears behind an electric wire? That’s just crazy. They’re lucky it wasn’t an adult bear or the outcome would not have been favorable for the guy who got dragged out of the tent, .44 magnum or not.