Visible crew/equipment: When Engine and Squad 51 are at the cliff with the young unconscious boy, Captain Stanley calls in to dispatch, with Stoker standing beside him. The reflection of the camera crane and location set lights are visible in the side door mirror.
Continuity mistake: When the boy who fell over the cliff is brought into the ER, Dix tells them to bring him to treatment 3 and we see them at treatment 3's door, which is on the same side of the hallway as treatment 4, with the red line closest to it (hall has red, green and yellow lines on the floor which run the length of the hall) However, in the shot from inside the treatment room, they're not in treatment 3, but are actually in treatment 1. Note that we see treatment 4 directly across the hall, which means they're in treatment 1, and also see the yellow line is closest to the door which means it's on the opposite side of the hallway.
Continuity mistake: On the way into the treatment room with the unconscious boy, Gage is on the left side of the gurney holding the IV bag. Suddenly, he's on the right side, away from the bed.
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.