Very difficult situation and without being there at the present time it is difficult to speculate expect for givng a theory or two.

Firstly communication withg the PH should have been taken before hand. For example if the only shot that would have been presented was a brainshot which is not an easy shot especially for a novice the PH should state that he will shoot if the ele doesn't drop which is fair I think considering that an elephant can travel fast and could get away.

On the other hand if a broadsiode shot was taken the ele would have obviosly have run for a while and the client could have given one or two more shots but with such a big target to shoot at it is much more easier to hit it than the brain then the PH should back off untill it is found that the ele is wounded or when it charges and gets to close.

BTW I wonder how many of Mark Sullivan clients have really killed their animals and how many as he killed for them