Revealing mistake: After Station 51 reaches the burning house, when Engine 210 rolls up and lays out a supply line, as the camera zooms in to the back of Engine 210, we can see the large, red, rectangular material that is adhered to the engine with the number 210 printed on it.
Peace Pipe - S2-E5
Continuity mistake: When Johnny calls in to Rampart, Brackett answers and presses the two buttons to record the conversation, then tells Johnny to standby leaving the two buttons depressed, while the drunk driver is brought in. In the next shot, a closeup of Johnny, Brackett tells 51 to go ahead, and in the following shots Brackett continues to listen to Johnny, but none of the buttons are depressed on the tape machine to record the conversation. Then when Brackett gets off the line, he actually presses the tape machine's off button, as if the buttons had been depressed and the conversation recorded.
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: When Brackett asks Early to see the patient (Jamie Farr) who belongs to an occult group and has no function in his right arm, Brackett's wearing a blue/white striped tie, Early's wearing a red/blue striped tie, and Dixie's wearing a uniform dress. However, in the previous and following shots, Brackett's wearing a blue/red/gold patterned tie, Early's wearing a solid black tie, and Dixie's wearing a 2-pc nursing uniform with pants.
Other mistake: After Battalion Chief tells Squad 51 to go to the elevator shaft, when Roy, Johnny and Jason enter the building, the DVD subtitles read that Captain Stanley says "Here, the elevator, it's jammed," when in fact it's the Battalion Chief who says that - Captain Stanley is not even with them. Additionally, Johnny asks, "Is somebody in here, Cap?" even though he's addressing the Battalion Chief, not Captain Stanley. Then it's Roy who asks for the oxygen, but subtitles read that Johnny asks for it.
Character mistake: When Brackett and Early are dealing with three squads at the base station at the same time, Squad 51 has two victims - father and son, Squad 18 has a pulmonary edema, and Squad 36 has only one bicycle rider with severe head injuries, because the second rider died, so the total is four out of five being dealt with. Back at the station, after Johnny asked Dixie about the condition of all the victims, he tells Roy that the father and son are both responding, so is Squad 18's pulmonary edema, and for Squad 36's bike accident, that "both" are coming out of the coma, which totals five victims. Then Roy responds, "Four saves out of five victims. That's pretty good." Johnny should not have said, "both" since it was just one rider.
Character mistake: Days after Drew's death (Roy and Johnny had two days off after Drew's death), during the meeting that Brackett has with the four paramedic units, one of 59's guys asks, "What do we do when we have this overload situation on the same frequency? Two squads, like 51 and us today?" The situation with the frequency did not happen "today" as he said, it happened at least three days prior.
Welcome to Santa Rosa County - S6-E10
Continuity mistake: When Roy and Johnny cross the road to talk to the sheriff about the injured rock climbers, Roy does not have gloves in the back pocket of his jeans or anywhere else, nor does he take gloves from the sheriff's trunk with the other climbing gear, before he and Johnny begin their ascent. However, when he reaches the boys, Roy has a pair of thick work gloves sticking out of his back pocket.
Visible crew/equipment: When Johnny is in the ambulance with the boy who ingested poison, the shadow of the cameraman holding the handheld camera is visible on Johnny as he sits beside the stretcher.
Propinquity - S3-E20
Visible crew/equipment: When Engine 51 first arrives at the abandoned refinery and stops to hook up to the hydrant, the multiple location set lights are reflected on the engine's large windshield.
Revealing mistake: When Squad 51 is dispatched to the man who has difficulty breathing, once they arrive and it cuts to a closeup, at the top of the screen there is a small dark film square that moves towards the left corner, and then it stays there in the following shots facing Johnny, until he contacts Rampart on the Biophone.
Visible crew/equipment: At Rampart, when Brackett walks over to Roy to speak with him about the birth of another baby, the actor's black tape mark is visible on the floor, just before Brackett stands there.
Continuity mistake: When Gail, Laurie, and Pete realize they forgot Melinda, Johnny is wearing his leather jacket when Roy says "Look, it's a boy," but in the next shot Johnny's jacket is gone when he asks what happened.
The Wedsworth-Townsend Act - S1-E1
Visible crew/equipment: When Dixie and Johnny are at the overturned car at the cliff, Dixie opens the car door and goes inside, and as the camera trucks to the right we can see a crew member, wearing a rust-colored shirt, reflected in the shiny bumper.
Visible crew/equipment: After the guys rescue the woman who was trapped upside down in the wrecked car, when they load her into the ambulance, the location set lighting is reflected on the glass of the ambulance doors.
Continuity mistake: When Johnny and Roy are at the apartment building with the broken elevator, Roy's watch is gone when they climb the steps, but he's wearing the watch when they enter the apartment, then it vanishes when they head back down. That watch reappears again, disappears and reappears until they go back up to the apartment for the second time.
Visible crew/equipment: When Johnny and Roy walk into the staff lounge, to join Morton, Brice, and the other paramedics for the tape review meeting, the two actors’ T-marks are visible under the table, where he and Roy are standing.
Visible crew/equipment: When Johnny is reading out loud from a transcript, while he and Roy head to the tape review meeting in the staff lounge, just after they turn the corner, the three tape marks are visible on the floor. One is for Johnny near the door, and two are for Roy - the first mark for where he originally stands and the second one for when he walks back over to Johnny.
Visible crew/equipment: When Roy, Johnny, and Morton leave the staff lounge talking about Brice, they stop at the nurses’ station, and when Johnny and Roy walk away, the two actors’ tape marks are visible where Morton is still standing and where Roy had just been standing. Additionally, the outlines of the lavalier mic transmitters are visible on the left sides of Roy's and Johnny's shirts, particularly when they stop at the fountain.
Visible crew/equipment: When the woman runs into the ER screaming that her son accidentally shot himself, as she and Brackett race to the door, the actor's black tape mark is visible on the floor behind her, where she had been standing.
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 ★