Revealing mistake: When Johnny and Roy are in the squad heading to Rampart after freeing the girl's toe from the bathtub, they get dispatched to 'possible electrocution' and we can see the white tape with "Kevin" inside Roy's helmet. (00:37:30)
Visible crew/equipment: After Captain Stanley's clam chowder lunch, the tones drop for the unknown type rescue, and when Cap hands Roy the piece of paper with the location, the reflection of a female crew member is visible on Squad 51's vent window, beside Roy.
Continuity mistake: When John and Roy are at the park with the injured football player and his son, the shadows that are cast over the entire area change significantly when the ambulance arrives.
Visible crew/equipment: While Squad 51 is parked at ER receiving, John and Roy tell Dr. Early about the squad's engine problem, and when Early fixes the engine problem, we can see the reflection of numerous set lighting on the squad's chrome spotlight.
Other mistake: After Dr. Early fixes the squad's engine problem, while Roy and Johnny are driving away, Roy's watch reads 10:30, but when the dispatcher sends them to the leg injury he says that the time out is 11:52. Then at the scene of the football player's leg injury, Roy's watch reads 8:15 and Johnny's watch reads 9:30.
Continuity mistake: When Johnny and Roy are on the "child locked in a bathroom" run, Johnny makes a hasty retreat leaving Roy to deal with the "child." The bar of soap Roy uses is on a curved pedestal soap dish, and that dish is either curved towards the wall, or turned the opposite way, depending on the camera angle.
Continuity mistake: When Brackett tells Morton that he can go keep Early company while he awaits test results, Brackett's wearing a patterned tie, and when Brackett walks into treatment 3 his tie is tied differently.
Visible crew/equipment: When Roy and Johnny are in the basket with the man who was electrocuted, after they finally get the victim on the ground and surround him, the shadows of the cameraman/camera are visible mainly on Roy and Captain Stanley.
Visible crew/equipment: When John and Roy get back to the station, Captain Stanley asks them to step into the office, and as Cap walks through the doorway the camera's shadow is visible on the wall at the left. Also note the coiled electrical wire lying on the floor in front of the squad, and the shadow of something that is directly in front of the squad, even though the squad just rolled in.
Continuity mistake: When Johnny and Roy are in the basket with the man who was electrocuted by a power line, they are atop three more power lines. Chet and Mike cut the two outer lines and only the center line remains, but in the closeup of the basket there are still three power lines under the basket.
Continuity mistake: After Dr. Early fixes the squad's engine problem, while Roy is driving we see a two-way radio mounted at the top of the dashboard, just past the steering wheel. When the dispatcher calls on Squad 51 to respond, there's a closeup of the Motorola two-way radio/Interceptor units which are mounted under the dash (near gas pedal), and Johnny lifts this mic, but then we see that he's speaking on the mic from the top of the dash. Additionally, in those two closeups of the two-way radio, we can see the gas pedal, but Roy's foot is nowhere to be seen, even though the squad has been moving all along.
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.