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.
Other mistake: During the fire at the horse ranch, when Engine 40 rolls up we can see that the engine company's number is covered atop the cab, and the large, red rectangular vinyl material that's adhered to the back of the engine with nothing on it. Presumably covering the real engine company's number.
Other mistake: When the dispatcher sends Squad 51 to the heart attack at the bank robbery location, the address is given as "2057 North Hillcrest, cross street Barker," but when they arrive at the corner bank, the sign reads Celis Street.
Continuity mistake: After John spots a cute nurse talking to Dixie, when he zeros in on Dix for the nurse's name Dixie's holding a pad in her left hand, but in the next closeup her left hand's empty as she gives John an entire run-down on that nurse.
Audio problem: After Johnny gets out of the elevator, Johnny sees a crowd around the treatment room, so Roy tells him that they're interviewing the bank guard who was shot, and when we hear Roy ask, "How'd you make out with the girl from orthopedics," his mouth is saying something different.
Continuity mistake: When Dr. Early and Marcia's father stand outside her semi-private room, number 104, we see treatment 4 is right beside it. There are two problems with this bizarre situation. First, when Dixie gave Early the lab results about Marcia's possible pregnancy earlier, treatment 2 is right beside treatment 4, not the semi-private room 104. Second problem is that when Early and the parents walk into Marcia's room, in the interior shots we can see that there's a perpendicular wall right beside the doorway to its left, where the hallway ends. (00:19:20 - 00:31:30)
Visible crew/equipment: When Station 51 arrives at the salvage yard's fire, Johnny gets out of the squad, and when he puts on his turnout coat as the camera zooms out, a dark haired crew member wearing a short sleeve white shirt is visible at the lower right corner of the screen.
Other mistake: When Station 51 is dispatched to the woman who fell through the ground into the abandoned well in her backyard, en route there's a moving bird's-eye view as the filming chopper follows 51's vehicles making a right turn. On the ground below, there are two people standing beside a blue station wagon, and one points up to the filming chopper flying overhead.
Revealing mistake: When Station 51 is dispatched to 'fire in the salvage yard', in the exterior shot as the squad and engine roll out of the bay, we can see the real Station 127's vehicle is still parked inside the apparatus bay, near the rear bay door.
Other mistake: When the dispatcher sends Station 51 to 26309 Barcelona Drive, as the squad pulls up in front of the house, the number on the mailbox post reads 4050.
Other mistake: At the end of the episode, when Roy, Johnny, and Chet are at their lockers, Roy comments that Gloria won't make the same mistake twice about the $8.42, and Chet laughs, but the subtitles read, "Marco laughing", even though Marco is not in the scene. Subtitles from Universal Studios 2010 DVD.
Other mistake: While John is searching through the papers for the receipt, when Roy takes the milk carton out of the fridge he pours some into a glass and some ends up spilling onto the floor, we can see there's black tape on the milk carton covering the brand name.
Visible crew/equipment: While the guys are at the table eating Marco's stew, when Johnny remembers that he spent $8.42, numerous set lights are reflected on the coffee pot's chrome surface.
Revealing mistake: When the guys are in the backyard with the woman who fell through the ground into an old abandoned well, in the overhead shot we can see the cuts that created the cutout hole on the flat surface around her, and that it's not really dirt or sand that she's slipping through.
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.