 What role does Doc play for Sandra?
Silently, so as not to shock anyone with illusions about well dressed young women, Sandra Lea Grayling cursed the day she had persuaded the Chicago Space Mirror that there would be all sorts of human interest stories to be picked up at the first international grandmaster chess tournament in which an electronic computing machine was entered. The many clocks, bedside table size, would have struck a familiar note except that they had little red flags and wheels sprinkled over their faces and they were all in pairs, two clocks to a case. Her last assignment had been to interview the pilot pair riding the first American manned circum-lunar satellite—and the five alternate pairs who hadn't made the flight. This tournament hall seemed to Sandra much further out of the world. Samples: "They say the Machine has been programmed to play nothing but pure Barcza System and Indian Defenses—and the Dragon Formation if anyone pushes the King Pawn." "I heard the Russians have been programmed—with hypnotic cramming and somno-briefing. Sandra's chief difficulty was that she knew absolutely nothing about the game of chess—a point that she had slid over in conferring with the powers at the Space Mirror , but that now had begun to weigh on her. "As for the Machine—you do know, I suppose, that it is not a humanoid metal robot, walking about clanking and squeaking like a late medieval knight in armor?" "Yes, Doc, but...."
 He plays an informative role.
 He plays a comedic role.  He plays a condescending role.  He plays an entertaining role.  He plays an informative role.