[tfm]

It takes real skill to walk in a straight line, even with a compass. The best navigator I know taught me the trick of lining up good landmarks and concentrating on those, head straight for them, then choose another, but by crikey it takes effort to do it even halfway decently.

This would almost certainly have been a case of answering the call of nature, going a very little way off-track to preserve decency, getting ever so slightly turned around to lose the trail, then an escalating series of "corrections" as it becomes clear that it's all going wrong. It's a very sombering and saddening thought.