Continuity mistake: When the guy (Michael Conrad) with the gunshot wound is being wheeled out of the treatment room there is nothing on his face, but in the shot from the hallway as they exit the room suddenly he has a tube inserted into his nostril with tape holding it in place.
Continuity mistake: When Roy and Johnny are on the roof with Harriet, we can see the shadow being cast by the utility pole on the street down below, and when the police car shows up moments later that shadow has changed significantly. (00:12:40)
Visible crew/equipment: During the structure fire, when Captain Stanley uses the HT and says "Engine 17, you can pump to Engine 51," in the next shot a second cameraman carrying a handheld camera is visible between Engine 17 and Engine 9, as he's shooting footage. He's visible again three shots later, standing beside Engine 17, and once again right after they lower the ladder through the hole in the roof.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.