That's the Kruger NP policy. You stay in your vehicle, because you are on your own. There are no end of people that have had problems because they ignored that advice.Another friend, when working in South Africa, drove into the Kruger NP. At one of the entrances, the reserve staff told him not to get out of his car, even if it broke down. Patrols were always about and they'd find him quickly if he did
They also said that a couple of weeks earlier a couple of German tourists decided to get out of their car to get closer to some wildlife to get better pictures
What they didn't see were the lions!
Game parks are different. Rangers escort you, so you can walk through the bush to see the animals close at hand, and we never had a problem. We walked within 25 yards or so of a pair of Cheetahs, a similar distance from a pack of wild dogs, and had other close encounters that will stay with me for life.
The rangers looked after us, never placed us in any danger, and I have nothing but praise for the professional way they safely guided us.