In 'Dance of the Dead,' when Number 6 is down on the beach, he sees the white membranic mass of the Village Guardian, and begins to run along the shore line. The Guardian doesn't attack the Prisoner, but keeps his distance, keeping pace with Number 6 as he begins to run faster. The scene gives the impression, and I favour this idea, that Number 6 is for some reason, testing himself against the Guardian. The Guardian appears to be Number 6's pace setter. But it is soon revealed that Number 6 cannot out-run the Village Guardian which eventually brings Number 6 to his knees, having run him into the sand!
I'll be seeing you