Don't ever confuse stopping an animal with killing it. In this case, I don't know what caused the bear to turn and walk away. Pain, fear, walking away from something that hurts? The shots didn't stop it, but certainly killed it. These shots may not have been enough to stop a large enraged bear. You have to have penetration and shot placement for vitals or central nervous system damage.
Brown bear in heavy brush on moose carcass at 75 yards detected hunter & 2 guides. He charged them, cleared brush at 20 yards, all 3 fired at same time...300 Wby, 338 Mag & 375...all hit bear in the chest.
The shots stopped the bear, knocking him back on his butt...guide said only time he has ever seen a bear stopped by bullets that didn't kill him.
Bear then rolled sideways, back on feet and continued the charge. All three fired again & bear dropped dead 7 yards from closest shooter.
Brown bear measured 9', killed 300 miles West of Anchorage.