And yes... that .458 sounds like it would be enough gun for just about any job!
Apparently they just drove right up next to prides of huge lions in an open Land Rover. The guides told them not to stand up or change the profile of the vehicle in any way when they were near the animals.
One lion had the remains of an antelope: two eyeballs, which it evidently didn't like, the horns, and a smear of blood on the ground, that was all that was left.
They were in a no hunting preserve, but once heard rifle fire from a nearby preserve that did allow hunting.