Revealing mistake: After the two drivers from the traffic accident walk off holding hands, and Johnny tells Roy what happened with Barbara, while Roy explains "body-language" to Johnny, we can see the white tape with "Kevin" inside Roy's helmet.
Visible crew/equipment: After the squad and engine pull up to the theater, when the manager of the band tells Johnny about the musicians wigging out onstage and then 51's guys follow him, the reflections of the camera dolly and moving crew members are visible on the surface of Squad 51.
Continuity mistake: After the cropduster crashes, when Roy and Johnny pull the pilot out of the overturned aircraft and begin working on him, Johnny's medical holster with penlight, forceps and scissor is clipped at his right hip and the other holster's at his left hip, but when Johnny shouts to Chet about giving the victim oxygen, Johnny's holsters have switched sides.
Continuity mistake: When Roy tells Johnny to call Barbara, who heard something that he didn't even say at the movies, in the view from the kitchen Engine 51 is not in the apparatus bay which means everyone else is on a run, but when dispatch drops tones we hear Captain Stanley respond KMG365, and then see the engine parked in the bay.
Visible crew/equipment: At the horse ranch, after Bill falls off the horse again while the squad is chasing after him, when Roy kneels beside Bill we can see the shadow being cast by production equipment, presumably the reflector screen, on the ground behind Roy. Then after John checks Bill's ears and pulse, just as he contacts Rampart for the second time, we see movement which looks like a sleeve on the right side of the screen, beside John.
Continuity mistake: When the guys are eating dinner talking about marriage, John's glass of milk is half full in the shot from behind him, but when Barbara calls the station and Captain Stanley answers the telephone, John's glass is nearly full in the shot facing him.
Character mistake: When Johnny and Roy respond to the 'possible injury at the horse ranch', after the guy who was knocked unconscious gets back on the horse, Johnny tells Roy, "Why don't we stick around for another few minutes, unless we get another call." They did not contact the dispatcher that the squad's available, so they would not even be dispatched to another call, since they're already on that run.
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.
Continuity mistake: While Roy and Johnny are working on the guy who fell from the horse, since Roy's hands are busy he has the IV line dangling from his mouth before setting up the patient's IV, and in wide shots the cannula is dangling at the left side of his mouth, but in closeups the IV line and cannula have switched sides.
Deliberate mistake: While Squad 51 is chasing after Bill, who's slumped over in the saddle on the run-away horse, one of the shots of Bill from inside the squad is a flipped shot. Note the landscape, as well as the shadow being cast on Bill's right instead of his left.
Visible crew/equipment: At the horse ranch, after the man falls off the horse John and Roy rush over, and as Johnny leans over him the bulging outline of the lav mic transmitter is visible on the back of Johnny's jacket.
Continuity mistake: After bringing in the atropine overdoses from the daffodil bulbs, in the shot from inside the treatment room when Roy and John leave treatment 3, which is opposite the nurses' station, they turn left to head towards receiving, but next shot they're walking from around the corner in the hallway, then pass that door they just left from.
Audio problem: After John starts telling Roy about how he and Barbara went to a movie, when Squad 51 is dispatched to 'man unconscious at Observation Park', we see a closeup of Roy in the squad as he puts the gearshift into drive, and then we hear the audio of the ignition being turned on.
Continuity mistake: After Roy tells Johnny to call Barbara, while they're standing by the telephone in the kitchen, Squad 51 is dispatched to 'man unconscious at Observation Park', and when the squad rolls out of the apparatus bay, the engine we see parked in the bay is the Crown from the first two seasons, not the current Ward LaFrance.
Continuity mistake: When the parathion victim is brought into the ER, they go into treatment 2, but in the view from inside the treatment room when John opens the door to leave, we can see that he's actually on the opposite side of the hall facing treatment 2, which means he's in treatment 1.
Continuity mistake: At the start of the episode, when Roy and John are going through inventory in the trauma and drug boxes, there are three rolls on the trauma box lid and John takes two of them leaving only one, but it cuts to another angle and now there are two on the lid.
Visible crew/equipment: While Johnny and Roy are with the unconscious man who ate daffodil bulbs, when the officer asks the bystanders to move back, the outlines of the lav mic transmitter and wire are visible on the back of the officer's shirt, when he turns around.
Visible crew/equipment: After they finally get an address for the attempted suicide Squad 51 takes off, and when Engine 51 pulls away from the curb, the shadow of cinematographic equipment is visible on the engine's front, and the reflection of lighting equipment is visible on the side of the engine.
Other mistake: When they're trying to identify the address of the attempted suicide, Engine 51 stops and is standing by at 223 Street and Ridgely, while the squad drives elsewhere, and when Squad 51 stops it's standing by at 218 Street and Carson. However, when they're dispatched we see that the rigs are actually pulling away from the same corner but facing opposite directions, note the area and background. Then when Johnny and Roy put on their turnouts, in the next shot of Engine 51 it's now driving towards the camera in the opposite direction on the same street they had pulled away from.
Other mistake: When Dixie's on the phone with the suicide attempt, Dixie tells her the date of her own birthday, hoping to get the caller's birthday in return. Then when the caller tells Dixie that the month of her birth is February, while Brackett's listening, they don't contact Early who's with the senior data analyst with that crucial information to help narrow down her identity faster, which was the whole point of Dixie trying to get that information from her.
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.