The reload was the issue in this charge. Moving and trying to load two rounds into the fairly narrow opening of a SxS double can be tricky regardless of experience. One advantage by the way an OU operates is that the wider opening angle makes a somewhat easier target to hit with reloads. And yes, I know that is heresy, so don't belabor it in comments until you have tried both. (Yes I own SxS's and OU doubles).
If the client had been using solids there almost certainly would have been two wounded animals. The first shot was a bit high and too far back. The fact they seem to have closed with the bull rather quickly suggest a rear lung shot.
Other than fighting the bolt toward the end, once things went south the client seems to have done pretty well.
I am frankly not all that surprised that the PH's reload wasn't that clean and automatic. These men are absolute pros, but few these days have ever been part of a dangerous game culling mission that were so common back in East Africa days. They actually have relatively little experience or practice going through a fast reload. It becomes harder to really replicate this sort of event with live rounds due to the prohibitive cost of such ammunition in Southern Africa.
@Foxi is correct. One more second of fumbling and the PH would have had that thing in his lap. The cameraman does indeed deserve to be mentioned in dispatches. Rather like airplane crashes, if you walk away, it was a good landing.