Revealing mistake: While the squad and engine are en route to "possible fire", one of the camera angles is from the POV behind Roy and John, where the back of squad is located. That’s fine, but the problem is that there's bright sunlight on their backs as they’re driving, when it should not be there. Artistic license is acceptable, but with so much sunlight where it should not be it reveals that Squad 51 is not in its normal state.
Revealing mistake: When Johnny, Roy, Vince, and the wounded officer are hiding between the bakery truck and car, before the multiple bullet holes actually appear on the side of the truck, those areas where the holes will show up have off-color markings, prepared for the stunt.
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.