Continuity mistake: When Early is examining the boy who had the grand mal seizure in the waiting room, after using his penlight Early puts it back into his pocket just before he examines the boy's ears in the closeup, but in the wide shot that penlight is on the gurney and Dixie picks it up then puts it into her pocket. Yet in Early's closeups the penlight is still in his pocket, and in the wide shots it's gone.
Continuity mistake: When Early examines the boy who had a seizure in the waiting room, Early uses a tongue depressor and his penlight to check the boy's throat. During his examination, in the wide shot the penlight is in Early's right hand and the tongue depressor in his left, but in the closeup they've switched hands. Additionally, in that wide shot Dix is holding the otoscope with her right hand, but in the closeup her right hand in under the boy's head.
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.
Continuity mistake: When Early walks into the staff lounge after Johnny's surgery, and joins Roy at the table, Early's holding the cup of coffee with his right hand in the shot facing Roy, but in the shot facing Early he's holding the cup with his left hand.
Continuity mistake: While Early is examining Johnny in the ER, telling Roy about symptoms for ruptured liver or spleen, in the closeup Roy's holding up the IV bag with his right hand, but next wide shot it's held up in Roy's left hand.
Continuity mistake: During this episode Brackett is wearing a tie with white, light blue, and dark blue broad stripes, which should be tied in an identical manner in consecutive shots, but it's not. One example is when Brackett examines the tree surgeon, but when he waits in the hall with Morton and Dixie while Malcolm takes x-rays, Brackett's tie is tied differently, and when he walks back into the room the tie reverts back.
Continuity mistake: When Roy's injured during the warehouse fire and is carried out, in the closeup he and Johnny are not wearing their turnouts, but in the next wide shot Johnny's suddenly wearing his turnout again as he contacts Rampart via Biophone.
Continuity mistake: When Johnny walks into the office to drop off the trash bin, he sees the Chief's clock on the wall and it reads 2:09, but when Johnny brings the clock to Captain Stanley and he gives it to Chet to hide, the clock's hands read 6:44. And when they're all dispatched, the timeout is 14:15.
Continuity mistake: When Karen asks Roy and John for an evaluation of that morning's run, a coffee cup suddenly appears near her arm, which promptly disappears, until Roy soon places his coffee cup near her arm when he sits down beside Karen.
Pressure 165 - S5-E7
Continuity mistake: After Johnny discovers that the white stuff he left cooking on the stove has turned green, Station 51 is dispatched to the structure fire, so everyone rolls on the call. When Johnny and Roy return, and Johnny decides to dump all the food he cooked, a large stock pot has mysteriously and conveniently appeared on the counter, where it did not exist when they left.
Above and Beyond... Nearly - S5-E20
Revealing mistake: Dixie and Brackett rush onto the elevator with a crash cart to go up to the third floor, for a possible MI in the dental clinic. The camera's POV is from the elevator, and in one continuous shot, without cutting away, we see the ER hallway through the open doors, then the doors close and in a few moments the doors open on the third floor. Even though the set has changed a bit, we can tell it's still the ER hallway by things such as the same scuff marks on the floor, and we can also catch a glimpse of the paramedic status board on the wall, where the base station room is located.
Involvement - S5-E19
Visible crew/equipment: On scene at the accident with the tanker carrying liquid hydrogen, after Chet extinguishes the fire that ignited on Johnny's back, when the fire spreads and the car explodes, the car falls onto its side and the FX stunt platform that the car was resting on becomes visible. Then two shots later that platform has vanished, as they hose down the fire.
Above and Beyond... Nearly - S5-E20
Visible crew/equipment: When Johnny and Roy get back to the station, and Captain Stanley tells them to come into the office where Chief Houts is waiting, the reflection of numerous set lighting can be seen on the squad's chrome spotlight.
Above and Beyond... Nearly - S5-E20
Continuity mistake: After Station 51 is dispatched to 'man stranded on a cliff', when Roy and John free climb up the cliff, they're not wearing their uniform shoes, they're wearing hiking-type shoes with ridges on the soles.
The Girl on the Balance Beam - S5-E18
Visible crew/equipment: When Johnny talks to Morton about the young gymnast and the responsibility of coaches and parents, the outline of the mic transmitter is visible on the left side of Johnny's shirt.
The Girl on the Balance Beam - S5-E18
Continuity mistake: When Roy and Johnny arrive on scene with the injured gymnast, as they enter the building in the exterior shot it's the last door that's open, but in the next interior shot that last door is shut, and it's the second to last door that's open.
The Girl on the Balance Beam - S5-E18
Continuity mistake: When Johnny and Roy are at the movie studio, while they're dangling from their lifelines they're trying to help the actress dangling from her own lines, but when she freaks out she drops her wand (yes, a wand) in the wide shot, but next closeup she's still holding it.
Visible crew/equipment: After Station 51 is dispatched to the landslide, when Mike pulls the engine over on the side of the street, as Captain Stanley and Chet walk past the front of the engine, the cameraman's and crew member's legs are reflected on the windshield.
Continuity mistake: When Mr. And Mrs. Merkle visit the station the first time, Mrs. Merkle's long, pointed blouse collar jumps under and over her sweater repeatedly.
Continuity mistake: When they pull Mrs. Merkle from under the wrecked car in the restaurant, the BP cuff is not visible around her right arm, but in her closeup she has the wide BP cuff around her arm with the gauge facing up, then in the wide shot once again the BP cuff is not visible.
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.