Visible crew/equipment: At the structure fire, right after Captain Stanley and Roy throw the rope down to Johnny and the boy, and Cap tells Marco to use fog, in the next overhead shot as the guys use the axe on the partition fire, at the right side of the screen we can see a crew member wearing a short sleeve grey T-shirt, who's standing at the stairway landing right outside the door, as he's using the FX smoke/fog machine which is blowing smoke through the doorway.
Visible crew/equipment: After Mrs. Mannering walks over to Dixie and asks about her son, when she and Dixie head to Brackett's office, the outline of the lav mic transmitter is visible on the back of Dixie's uniform, and a bulge is also noticeable on the back of Mrs. Mannering's sweater.
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.