Heavyweight - S3-E5
Continuity mistake: At the start, after Station 51 is dispatched to the apartment fire, when a musician asks Captain Stanley for help removing instruments from the burning building, the next shot showing Truck 98 rolling up is footage from 2x13, "Drivers", during the fire at the Atlas Hotel. We can even see the smoke through the Atlas Hotel's windows, and Squad 51 parked across the street. More footage from the Atlas Hotel fire is shown when Engine 16 rolls up. Additional footage from other episodes are shown as well, when we see helmets and rigs bearing company numbers that were not called to this fire.
Heavyweight - S3-E5
Continuity mistake: When the little boy who received an electric shock is brought into the ER, in the shot from the hallway he's taken into treatment 4, which is beside the nurses' station, but in the next shot from inside the room, we can see treatment 2 on the opposite side of the hallway, which is next door to treatment 4. This means they're actually in treatment 1, not 4.
Heavyweight - S3-E5
Continuity mistake: At the structure fire, after Roy helps the pregnant woman down the stairs, when Johnny brings the O2 and blankets for her, we see that Johnny's wearing a SCBA tank with no markings. However, after Roy tells Johnny to take off, when Johnny hurts his shoulder, his tank has two large stickers - a white and a red.
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.