I will just echo all the sentiments above.
Man that was a little hard to watch. I think the bull was rut crazed and injured and just didn't really see that one coming. Gotta admire that bear's determination it earned that meal for sure.
I'm actually reading a lewis and clark biography right now and in the days of grizzlies not fearing humans, basically their strategy was either shoot it, and if it still was running at you, go into the river for safety (they were traveling up the missouri and were basically always by the river). I think a human would escape in the water with a little more intensity than that bull, he didn't seem too worried about the threat. Two very impressive animals doing their thing.