The Promise - S3-E11
Other mistake: Richard is in room 603 and jumps out of the 6th floor hallway window. In the long shot of the exterior of the building, we see that he's lying on the ledge of the row of windows that are second from the top. The elevator shows 8 floors, which means that he's actually lying on the 7th floor's window ledge.
The Promise - S3-E11
Other mistake: At the very end, when Roy is cleaning the windshield while John's fiddling with the squad’s radio mic, the spray can on the hood of the squad has tape covering the brand name.
The Promise - S3-E11
Other mistake: When Johnny and Roy get back to the station, Chet tells Johnny that Paula's going to come by around 12:30 PM, then when the dispatcher sends Squad 51 on the 'woman down' run he says "Time out 12:22." When the guys get back to the station again, Paula tells Johnny that she arrived around noon and that Engine 51 left on a run shortly after.
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.