Revealing mistake: When Captain Stanley runs into the burning house looking for Johnny, the floor beside the stairs (under the table) is visible behind him, and there is no rug only wall-to-wall carpet, but when Johnny and Toby fall from the stairs, that area of floor is covered in a rug raised up like a platform, covering the crash mat for the stunt, then the rug vanishes when the guys get Johnny and Toby.
Other mistake: At the start of this episode the tones drop and Station 51 is dispatched to a fire and explosion. In this closeup, all the guys come running from the kitchen into the apparatus bay and head for the vehicles, but wait, none of them are actually 51's guys.
Continuity mistake: When Johnny is in the pool with the guy who somersaulted off the roof, he and Roy insert an esophageal airway to ventilate, but when they lift him out of the pool and load the guy onto the stretcher, the esophageal airway has vanished.
Visible crew/equipment: When the attendants wheel the boy who can't breathe into the ER, then stop at the nurses' station so Morton can have a look at him, there are two white tape marks visible on the floor, one is below the base station's tape recorder, where a nurse first stands, and the other is at the side of the main desk, where that same nurse (behind Dixie) stands a moment later.
Other mistake: When Roy and Johnny are with the guy who somersaulted off the roof into the pool, Johnny is in the pool giving him oxygen, and in the closeups Johnny's left hand varies between very hairy, not hairy at all, normal fingernails and bitten up fingernails. Additionally, the hand holding the mask on the boy's face changes back and forth between Johnny's left and right hand, between shots.
Continuity mistake: At the start, when Station 51 is dispatched to the fire and explosion, in the overhead wide shot we see Gage getting into the squad on the passenger side, but in the closeup Gage is in the driver's seat, and when they arrive at the scene it's DeSoto who's driving.
Visible crew/equipment: While en route to the structure fire, Mike is driving Engine 51, and seated backwards in the jumpseat behind Mike is Marco, who's wearing a helmet and his turnout, but in the shot from the POV behind Mike, we see the reflection in the rear-view mirror of the grey haired crew member, who is seated facing forward behind Mike.
Continuity mistake: When Mrs. Epps begs Dr. Morton to tell her the truth about her son's condition, the stethoscope is hanging around Morton's neck with the headset on his left side and the chestpiece on his right side, but then it flips to the opposite way, and then back again, between shots.
Continuity mistake: When Johnny runs inside the burning house to get to Toby and his grandfather, he's wearing a distinctive SCBA tank on his back, but when Johnny's inside the house he's wearing a different tank. Additionally, when Roy takes the mother's pulse he's also wearing a tank, but when Johnny and Toby have come out his tank is different.
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.