Continuity mistake: Dispatched to the structure fire are Station 51, Engine 36, Engine 116, and Truck 3. While Johnny and Roy are searching the rooms for the young girl, it cuts to a shot of guys from 9, and later there are also shots of 28's and 19's guys, even though none of their companies were called to this incident. These are shots from previous episodes including 3x7, "Promotion."
Continuity mistake: When Station 51 is dispatched to the landslide, the address is given as 2283 Canyon Road, but when they arrive at the house the address is 4102.
Continuity mistake: When Ruthie is wheeled into the ER, Dixie tells the attendants to put her in the treatment room where Dr. Early's waiting, and they wheel her into treatment 2 which has a windowless door, but when they're in the room the door has a window, which means she's in treatment 1, not 2. Plus the fact that both treatment rooms are set up differently.
Continuity mistake: Immediately before the man rescued from the sewer fire is brought into the hospital, the shot shows squad 51 and two ambulances in all three spots in the ambulance bay, however neither ambulance is the big box Mayfair type that was at the rescue scene. (00:11:20)
Continuity mistake: When the guy who was injured in the manhole is brought into the ER, Dix tells them to bring him to treatment 6 (which is around the corner from the other treatment rooms, and has no color lines that run past its door), then we see him wheeled into treatment 6 in the shot from the hallway. However, in the next shot from inside the treatment room we can see they're not in treatment 6, but actually in treatment 1, note the red, green, and yellow lines on the hallway floor in front of its doorway, and treatment 6 has no color lines that run past its doorway.
Continuity mistake: When the TV catches fire in the kitchen, Captain Stanley unplugs it, and when it cuts to Roy running into the kitchen with the fire extinguisher, he passes Marco, who just ran into the apparatus bay. All of this while we hear Cap's voice telling Marco, who already ran out, to get the asbestos blanket. Then, in the next shot, Marco is still standing behind Captain Stanley in the kitchen.
Continuity mistake: When Johnny's on the phone with Uncle Ernie about the new color TV, in the wide shot Johnny writes down the address of the warehouse, and puts the pen back in his shirt pocket. Then Johnny thanks Uncle Ernie, and when he hangs up the phone, in the next closeup the pen is back in Johnny's hand.
Continuity mistake: When the boy who fell over the cliff is brought into the ER, Dix tells them to bring him to treatment 3 and we see them at treatment 3's door, which is on the same side of the hallway as treatment 4, with the red line closest to it (hall has red, green and yellow lines on the floor which run the length of the hall) However, in the shot from inside the treatment room, they're not in treatment 3, but are actually in treatment 1. Note that we see treatment 4 directly across the hall, which means they're in treatment 1, and also see the yellow line is closest to the door which means it's on the opposite side of the hallway.
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: Squad 51's lightbar has a center chrome piece which has slats at the front and is solid at the back. When the squad's dispatched to the vehicle accident with the two student drivers, on scene the lightbar's chrome center is on backwards, it's solid at the front for some inexplicable reason.
Continuity mistake: After Roy gets his leg bandaged at Rampart, as he and Johnny exit to their truck, they suddenly get haircuts. Looks like a shot from an earlier season.
Continuity mistake: When Station 51 is dispatched to a structure fire (with the two girls trapped upstairs) the address given is 1911 Harper Ave, but when they reach the house with the fire, directly across the street that house number is 1637.
Continuity mistake: When the unconscious boy is brought to the ER, he's taken into treatment 2, with a windowless door, but when Early is doing the lumbar tap on the boy, the door behind Early has a window, and also by the way the room is set up, we know it's treatment 1 he's in, not 2.
Continuity mistake: When dispatch drops the tones at night, waking all the guys up, notice that Marco's mustache has vanished, though it reappears later. Additionally, they all get into their boots, turnout trousers, only white T-shirts, suspenders, and grab their dark jackets, but when the bay door opens they're dressed in their uniforms as they respond. Then at the fire they're in the turnout trousers, and Johnny and Roy are wearing the uniform shirts when working on the burn victim.
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.
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.
Continuity mistake: When they pull the man with chest pains from the pickup truck, Dixie says treatment 3, which is opposite the receiving entrance and on the same side of the hall as the nurses' station, closest to the red line on the hallway floor, but when Dixie leaves the treatment room it's at the side of the hallway closest to the yellow line, and since there's a window on its door we know it's actually treatment 1 that he's in, not 3.
Continuity mistake: At the restaurant, when they begin to work on getting Mrs. Merkle out from under the car, Vince sets the Biophone down on the table, and there's a netted, red glass candle on the table, but in a following closeup the candle's net has vanished and it's pinkish clear glass now. Other items on the table change as well.
Continuity mistake: When Roy and Johnny go to get on the helicopter they are with only the orange bio-phone, but after The Boat brings them back to the shore you see them running to the helicopter with the patients, and they pick up their large black trauma box. They didn't have it with them when they left.
Answer: I was rewatching a few first season episodes of Charlie's Angels (1976), and in S1xE6 "The Killing Kind," I recognized the same actor. So, to finally fully answer your question, the two baseball players in School Days are played by Rod Perry and Sean Fallon Walsh.
Super Grover ★