It's How You Play the Game - S4-E19
Continuity mistake: When Squad 51 dispatched to 'man bitten by animal', the center chrome on lightbar is a solid piece, but en route the chrome center is striped and its trim is covered with black tape. Then when they approach the car lot, the black tape is gone.
Continuity mistake: When the cardiac patient is finally brought to the ER, and goes into full arrest number four, he's wheeled into treatment 1 which does not have a window on its door, but in the next shot from inside the room the door has a window, and when they're defibbing him, we can see the nurses' station outside the door, which means he's now in treatment 3, not 1.
Continuity mistake: After the Bengal tiger jumps on Les, the feline walks up the aisle that is directly in front of the self-serve ice cream freezer, and knocks over the pyramid of Hi-C cans that block the aisle, but a few shots later the tiger walks up that same aisle (note the ice cream freezer), and the mess of Hi-C cans have vanished.
Continuity mistake: After Johnny sees the Bengal tiger in the market, he backs away, and when Johnny is about to walk through the curtain, in the shot from the back room we see the tall shelving display of chip bags on the other side. However, in the next shot from the store that display of bags is gone, there's only a display of loaves of bread in front of the fruits and vegetables.
Continuity mistake: After Roy and Johnny's pre-dawn rescue at the market, by the time Roy advises dispatch about the tiger and when Animal Control shows up at the market, it's already past sunrise, but when Les and the officer walk into the store and then when they follow the tiger up onto the roof, it's nighttime again.
Smoke Eater - S4-E16
Continuity mistake: When Station 51 is dispatched to the structure fire including a chemical lab, Johnny and Roy put on SCBA tanks with distinctive markings/stickers before going in, but those tanks change while inside and when they exit with the victims of chemical smoke inhalation.
Continuity mistake: While on the way to the parade in The Old Engine, when Johnny and Roy deal with the fire rescue and reach the roof, Johnny has a rope bundle swung across from his left shoulder to his right hip. However, in the next shot as they run across the roof, the bundle is now swung from his right shoulder to left hip, and the rope is also bundled differently.
Continuity mistake: When Roy and Johnny get back to the station, Johnny asks Chet about the condition of the house after the fire, and in the wide shot Johnny has a really red pimple near his chin, but in his closeup the pimple has vanished, only to reappear in the next shot.
Continuity mistake: During the house fire, when Chet kicks the door twice he leaves dark marks on the door, but when he kicks the door a third time the marks on the door have vanished.
Continuity mistake: When Dr. Morton leaves the room of the patient who attempted suicide to get Jack, he takes the pill bottle from Dr. Early, carries the medical chart holder, and is wearing a stethoscope around his neck, but in the hallway when he gets Jack the pill bottle and chart holder are gone, and the stethoscope is in his pocket. Then, when they walk back into the room, Morton's holding the bottle and chart holder, and the stethoscope is back around his neck.
It's How You Play the Game - S4-E19
Continuity mistake: When Johnny is in the ambulance with the car salesman that was bitten by the tiger, Johnny opens the man's shirt, but does not remove his western tie scarf. However, in the man's closeup the tie is open with the scarf slide removed, and then it's back to being tied with the slide.
Continuity mistake: When Chet and Marco are hosing the gas meter fire, they are both wearing gloves while handling the hoses. However, after Roy helps Chet up from his stumble, there is a closeup of the hoses and it's a bare hand handling the hose.
Continuity mistake: When Roy and Johnny are driving to the parade in the fixed up old engine, they repeatedly switch between the road's right lane and left lane, depending on the camera angle.
Continuity mistake: When Squad 51 and the ambulance arrive at Rampart with the father and unconscious diabetic son, the type of ambulance that backs up to the ER entrance is a station wagon, but in the interior shot from Rampart the ambulance type is a truck.
Continuity mistake: When Johnny and Roy are treating the officer, while hiding between the bakery truck and car, the sniper fires at them which leaves multiple bullet holes on the side of the truck. However, when Vince talks to the Sergeant on the handie-talkie and then fires the tear gas, all the bullet holes on the truck are gone, but they soon reappear.
Continuity mistake: The window from which the sniper is firing sustains damage with broken glass panes, but then the glass panes are whole and intact, and then they are broken again.
Continuity mistake: When Dixie goes to the waiting room to get Pete Barlowe so she can bring him to see Brackett, we see Carol, the nurse with black hair, working behind the admitting desk, but in the next shot Carol is in the treatment room with Brackett and Pete's wife.
Continuity mistake: When the guys come out and are watching Herbert leave, they are all in their turnout pants. Stoker is wearing turnout pants with the blue jacket zipped. When the tones drop for the call, the guys go to the vehicles and grab their turn out jackets and Stoker is in his blue pants and blue shirt pulling on a turnout coat. Not turnouts and no navy jacket.
Continuity mistake: When Gage goes into the lion enclosure you see the lion up high roar with sharp white teeth but the other shots the lion is now an older lion with broken rotten looking teeth.
I'll Fix It - S4-E2
Continuity mistake: While Roy and Johnny are under the house with the oil eruption trying to free the trapped man, they get covered in black oil and mud even though they're wearing turnout coats. It drips down their necks and their pants are soaked with it. When they get to Rampart with the victim, Roy says that he and John should get washed up, but when they talk to Dixie they haven't just washed up, their clothes are now impossibly spotless.
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.