You don't mess around with the king. Sheesh what a power house. Notice the roll to the back once he got the hyena so that he could bring his hind feet in to rake the belly? I see it every day with our cats at play and think that there is a fine line between pet and wild animal I don't often appreciate.
Just the other day another great nature doco was on called Hippo Beach.
A couple of things I didn't know about were the dominant male often just has to use "the look" and that Hippos have a reverence much like elephants over the dead of their kind. Again a demonstration of a herd backing off scavengers, again hyena, for a while as they examined and touched the corps.
Eventually they relented and nature took it's course.
I expect that bull we saw in Karries video was the dominant male just doing his thang. Excellent vid you found there.