Sorry but I don’t really get what point you are trying to make ?
Yes I do, maybe it 400 or something?…..I’m sure the bloke didn’t have a range finder ?, maybe he walked it after ?
Point is, because you have never seen it done don’t mean it can’t be done.
As C Green said earlier, get out and about right round the country on all types of terrain with blokes who ain’t clowns and you will learn something new every day……most of all you will learn that anything is possible with the right dog in the right hands.