Audio problem: When Roy and Johnny are tending to the actor with possible MI, Brackett asks for an EKG strip, and after Johnny hooks the scope up to the Biophone, we hear him say, "Lead 2," but his mouth is closed and doesn't move.
Other mistake: While the guys are in the kitchen, deciding whether or not to keep the dog and then what to name him, when Chet is drinking the milk, we can see the red tape covering one side of the container to hide the brand name and logo.
Other mistake: When Squad 51 is dispatched to the movie studio, while en route in the interior shot, in the rear-view mirror we see the reflection of the driver's helmet, and it has an 18 on it, instead of 51.
Other mistake: When the boy is brought to the ER by his babysitter, they hook him up to the ventilator and we see the bag dramatically showing inflation and deflation in the closeup, but in the wide shots the bag is deflated and doesn't move.
Continuity mistake: When the man who doesn't speak English is in treatment 4, there's a closeup of the Datascope 850 monitor, and then the girl points to the EKG monitoring unit behind the gurney and asks Dixie why the thing is bouncing up and down. Problem is that the Datascope 850 is used by the paramedics and it's not actually in that treatment room. The treatment room has a Zenith Travenol unit.
Continuity mistake: When Squad 51 is dispatched to the attempted suicide, the dispatcher states that he's in apartment 2A, and when Roy and John arrive at the scene the police officer also says he's in apartment 2A, but when they get to the second floor they pass apt 2A and go to the apartment at the end of the hall.
Pressure 165 - S5-E7
Other mistake: When Johnny brings in the bags full of groceries for the dinner he's cooking, and also later when he discovers that the liquid in the pot turned green, there is tape covering the brand names on the packages.
Revealing mistake: When Station 51 responds to the traffic accident, after Captain Stanley hands Johnny the Ajax tool, in the closeup it's obvious that the hands are not really Johnny's. Then there's another shot of the real Johnny, but once he removes his goggles, interestingly it's the stunt double who's in the following shots by the car, even when Johnny cuts himself, it's the stunt double.
Continuity mistake: After Station 51 is dispatched to 'traffic accident, victim trapped', when they get the anti-shock suit on the boy Roy's watch reads 5:25. Then at the hospital, when Johnny asks Roy about the time, Roy looks at his watch and says "About 5:00."
Continuity mistake: On the airplane, when Roy asks Johnny if he knows the flight attendant's name yet, the headset is around Roy's neck, but in the closeup it vanishes, then next shot it reappears again.
Other mistake: At 6:50 AM, just before the dispatcher transmits the testing tones to Station 51 which wakes everyone up, we're shown the exterior shot of the station and the two flags are already flying. Guys of C shift (as Chet states) haven't arrived yet that morning, so they didn't raise the flags, and we know it's Mike who always raises the flags on A shift, but he only just woke up when the dispatcher sent the tones.
Other mistake: When Station 51 is dispatched to the structure fire, the address is given as 1127 West Winston, but when they're on the scene, the fire flashes through the front door causing Marco and Chet to fall back, and the house number on the stairs is 1026.
Daisy's Pick Blind Date - S4-E7
Other mistake: When Johnny and Roy are in the ice house, there's a closeup of Johnny's arms as he's hosing down the ice and removing it from the hypothermic victim's arm, but it's obvious that the dark hairy arms belong to the stunt double, not to Johnny.
Other mistake: When Johnny and Roy are at the construction site with the injured father and son, Rampart is also on the line with two other squads - Squad 18, treating a pulmonary edema, and Squad 36, treating a bike accident. When Marco and Chet carry up the stokes basket, we hear the dispatcher saying, "Engine 21 and Squad 18, heart case...," even though Squad 18 is already tied up with the pulmonary edema.
Character mistake: When Johnny is about to tell Roy what the problem is, the dispatcher drops tones and says "Station 51, Engine 36, Truck 116, small aircraft in trouble.," but when Captain Stanley responds we hear him say, "Squad 51, 10-4...," even though he should have said, "Station 51, 10-4...," because both Engine 51 and Squad 51 were dispatched.
Other mistake: On Emergency! there's a noticeable lack of blood (not that it's a bad thing), even on the medical disposable gloves, during numerous scenes such as when a victim has arterial bleeding from carotid, brachial, and femoral arteries, or during the surgical procedures, and the labor/delivery scenes.
It's How You Play the Game - S4-E19
Audio problem: At the scene of the vehicle accident, Johnny asks the driver, "Where does it hurt?" but when he continues to ask, "Right here?" we can see he's not actually moving his mouth, just before he's punched in the nose by the driver.
Camera Bug - S4-E10
Other mistake: At the end of the episode, when Johnny's telling the other guys that his photograph was bought, the box of cereal and carton of milk that are on the table have tape affixed to them, to deliberately cover their brand names.
Other mistake: When Squad 51 is dispatched to the liquor store shooting, en route they are almost hit by a driver who passed a stop sign at the intersection. This is the same footage from season 2, episode 13 "Drivers", when the squad is almost hit by a car while responding to a football injury.
Other mistake: When Roy and Johnny are working on the squad's engine, while Johnny's lying on the mechanic's creeper, Roy is holding a spray can with white tape wrapped around the top of the can, so the brand name would not be 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.