You have never felt fear quite like weeing in the great outdoors and hearing the calls of an approaching dog walker. It sets your heart racing to hear those, "Come here!"s and indiscriminate, "yups" and, "ops." And suddenly, you're pulling faces and waving your hands frantically willing yourself to WEE FASTER.
The dog walker itself is not the problem. The dog walker will not see you, because presumably you had enough sense to widdle in a concealed spot away from the general public (unless you're into that). The problem is the dog, that will indiscriminately sniff you out and stare for an age while its owner is encroaching and calling, "Charlie! Charlie, what are you doing?" And all the while your bladder keeps finding more liquid to squeeze out.
You have never felt fear quite like it.
Unless you are or ever were a teenage boy and then I imagine you've experienced a fear exceedingly similar.