Yeah, I'm not clear either what they mean by diving.
Eva Twardoken's father was an exercise physiologist who once wrote an article called something like, "The Quickest Way Between Two Points Is Not Always A Straight Line." It was regarding skiing specifically, but the idea was that in certain circumstances, a curve would actually move the skiier more quickly to the destination than a straight line could. The curve had some cool physics name I can't think of right now.
Funny aside, the genious editors at the magazine that published the article revised the title to be "The Shortest Distance Between Two Points Is Not Always A Straight Line," which is of course not true and made ol' George T. sound like a dipshit.