Continuity mistake: During the fire at the apartment complex, when John and Roy go into the apartment to rescue the woman, they throw a coat over her, but then the explosion occurs knocking John and the woman unconscious. When Roy puts her over his shoulder and starts walking out the coat is not over her, but when he gets to the balcony she's covered by the coat, yet when the Pasadena fireman goes back for John, that coat is still lying on the floor.
Visible crew/equipment: At the site of the vehicle accident, the outlines of the lavalier mic and wire are visible on the back of Roy's shirt, particularly when he's with Eddie as his father's being taken in Copter 10 to Rampart.
Visible crew/equipment: After Engine 51 and Copter 10 are dispatched to the "traffic accident with injuries" Engine 51 is instructed to switch to frequency 3, and when Copter 10 takes off with Brackett, the moving shadow of the filming helicopter is visible near the shadow of Copter 10 chopper. (00:09:10)
Visible crew/equipment: After landing at the base camp, when Brackett and the others walk away from Copter 10 we hear the comment, "The coffee's lousy but the food's great," then we get a bird's-eye view of the base camp, and can see the moving shadow of the filming helicopter at the lower right corner of the screen. (00:06:20)
Revealing mistake: After Station 51 is dispatched to the 'plane crash into a structure', when Engine 51 pulls over to lay the dual lines at the hydrant, we can see up the block on the left, the back side of the apartment complex where they are headed, and most of the back windows are boarded up. The following scene takes place at the front doors of those apartments, where people supposedly live. The show used some real locations (not just Universal's sets) where there had been real fires, to film carefully controlled fire scenes.
Continuity mistake: At the start, there's a long shot of the Land Rover driving down a long stretch of road towards the camera and then passing it. That road, landscape, and mountains are very distinctive. As Roy, John, and Chet continue talking and driving, when they reach the scene of a traffic accident, Chet sets up a flare behind the Land Rover and another flare behind the pickup truck, then Chet sees a car coming from the direction which the Land Rover was headed. The problem is that the road/landscape/mountains shown earlier in the long shot of the Land Rover, which had been driving from the opposite direction, is the same that's shown here, as Chet tries to stop the car. Then to top it off, when Chet first notices the second car in the distance, it's coming from the opposite direction of the first car, but once again the view is exactly the same.
Visible crew/equipment: When all the guys are standing around the kitchen table, while Captain Stanley rips the paper so they can draw lots for using The Boat, the actor's tape mark is visible on the floor by Mike's foot.
Visible crew/equipment: At the start of the episode, in the closeup shot of Roy, Chet, and Johnny as they're talking about not catching any fish on their trip, there is a chrome spotlight on the roof of the Land Rover, and we can see the reflection of the camera mounted on the vehicle's hood.
Visible crew/equipment: After the two guys fill the fish tank with water, when they walk out of Brackett's office Dixie walks in, and as she comments that the tank is classy, the actor's tape mark is visible at her feet, in front of Brackett's desk.
Visible crew/equipment: When Roy and Johnny pull into the parking space near the car with the toddler inside, as the camera moves we see its moving reflection on the side of the car. Then when the woman says "Certainly something's wrong with him, he's unconscious," as the camera pulls back we can see its reflection in the car window. We can also see the reflection of the large location lighting when Johnny tries to unlock the door with a wire hanger.
Continuity mistake: After Brackett gets off the phone with Dr. Meier, he walks back to treatment 1, and when Brackett speaks to Morton about the patient being on warfarin, the stethoscope around Brackett's neck vanishes in his closeups, and reappears in wide shots.
Visible crew/equipment: When the attendants wheel the boy who can't breathe into the ER, then stop at the nurses' station so Morton can have a look at him, there are two white tape marks visible on the floor, one is below the base station's tape recorder, where a nurse first stands, and the other is at the side of the main desk, where that same nurse (behind Dixie) stands a moment later.
Other mistake: Roy and Johnny are in the squad when they're dispatched to the fire at the junior high, and 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.
School Days - S2-E14
Other mistake: At the start of the episode, the milk carton that Johnny takes out of the fridge has red tape covering the brand name and logo.
Visible crew/equipment: When the dispatcher drops tones for the trapped victim of a traffic accident, just after we hear Captain Stanley say, "KMG365," we can see movement between the front passenger and driver seats of Engine 51, precisely where the camera is. Captain Stanley is still at the radio base station and Mike hasn't opened the door yet.
Continuity mistake: When Johnny and Roy are with the heart transplant patient who is having chest pains, after they contact Rampart, in the wide shots Johnny has the stethoscope around his neck, but in his closeups the stethoscope is gone.
Revealing mistake: At the gas station with the broken pump nozzle, Captain Stanley and the station attendant head to the garage area to see the main shut-off circuit box, which is located at the far right corner of the garage, but in the next shot, we can see the attendant's reflection behind Roy, and he's standing somewhere else off camera, not where he's supposed to be in the next shot with Captain Stanley.
Visible crew/equipment: When the woman staggers into the ER a nurse rushes over, and the actor's T-mark is visible on the floor in front of the admitting desk, where the nurse was just standing.
Visible crew/equipment: After Station 51 is dispatched to the fire at the refinery, when they reach the refinery and make a right turn the view is from atop Squad 51's roof, and the reflection of the covered camera and part of the cameraman's head are visible in the squad's lightbar.
Visible crew/equipment: After Squad 51 is dispatched to the 'heart attack' at Compu-Data, when Johnny and Roy walk in and then approach the victim in the office, the reflection of the moving camera dolly is visible on the office's large panes of glass. The camera equipment also casts a shadow on the three men as they walk toward the office, then on the glass as it moves back and forth.
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 ★