What would have been the result if he'd been injured badly enough to stop him from walking?
While the article says dingos, I'm more inclined to say it was wild dogs, there are precious few pure dingos around any more and they are timid even in a pack. Wild dogs can look just like large dingos but unlike their pure counterparts are far more aggressive in numbers.
There are plenty of stories of injured people in the outback with dogs nearby; the happy ones are rescued in time.
Very lucky to walk away; I wonder what happened to the engine.