I was only 10 years old when I saw this episode, but I remember parts of it vividly. Perhaps I was struck by the gamesmanship of the story. Also, I think this was my introduction to psychological thrillers, at least on the small screen.
David outwits the master on his own turf, but barely. It takes every ounce of his intellect and experience to survive the episode, and he does so with scars. His opponent is a twisted version of McGuyver, who can apparently rig anything to do anything he wants.
Concur with the other ratings of superb to perfect. This episode haunted me for many years, and I still think about it once in a while. Like to see it again, to see if any of the initial impact has worn off. I'll bet not.
I'm not certain what the theme is; life is a game and humans the most dangerous? One freak of nature deserves another? Who best to outwit a master but another?
The most memorable episode of the series, and I saw more than a few, even if it was almost 30 years ago.