Other mistake: When Roy's talking to Dixie while John's waiting out in the squad, a call comes over the HT that Roy's holding, and Squad 51 is asked to respond to a 'possible heart case'. Roy pulls a piece of paper out of his pocket, and as we hear the dispatcher giving the address, we can see Keven Tighe softly mouthing the address at the same time that it's being given for the first time.
Other mistake: When the boy is brought to the ER by his babysitter, they hook him up to the ventilator and we see the bag dramatically showing inflation and deflation in the closeup, but in the wide shots the bag is deflated and doesn't move.
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.