Visible crew/equipment: At the scene of the traffic accident, after Captain Stanley tells Johnny and Roy that the victim may have a fractured pelvis, just as Johnny places the Biophone on the roof of the car the camera's angle tilts down to face the victim, and we can see the reflection of the cameraman/crew member on the car window.
Visible crew/equipment: When Squad 51 is dispatched to 'man unconscious possible heart attack', while en route, two shots after Roy says "It's gonna be a long run," the reflection of the squad is visible on windows they drive past, and we can see the reflection of a crew member who's standing on the back of the moving squad. Slow motion is not necessary to see this. However, if you're into slo-mo you can catch it again later, when John and Roy head to the traffic accident victim.
Visible crew/equipment: During the rescue at the jail, while Roy is hanging on the line, the outline of the mic transmitter is visible on his shirt at his left side.
Revealing mistake: During the rescue at the jail, while Roy tries to get a safety belt around the prisoner's waist, the man freaks out, then grabs Roy and they both swing out on Roy's safety line. When the camera pans a bit too far to the left, we can see the edge of the fake "sky" screen on the left, behind the building's replica set used for closeups.
Other mistake: When all the guys are sitting around the table discussing the paramedic problem, while Chet is looking in the fridge for the ketchup, we can see the milk containers on the door have their brand names covered.
Other mistake: While Roy's in the ambulance with the woman who fainted, when she holds out the bag of potato chips, we can see the large brand name on the front of the bag is covered with red tape in two places. Though they neglected to cover the small 'Lays' brand name on the side of the bag.
Other mistake: At the start, while Johnny is cleaning the oven, we can see that the oven cleaner spray can has tape covering its brand name, and anything else on the can that gives away the name of the brand.
Visible crew/equipment: When Johnny is kneeling on the sidewalk beside the woman who fainted, the outline of the mic transmitter can be seen at his left side, above his belt.
Revealing mistake: On the roof of the jail, Roy buckles his safety belt around his waist, with an extra belt for the prisoner hanging from it as well. When Roy removes the second belt from his own, we can see two carabiners that are now attached to his lifebelt, which go down into Roy's pants. Those carabiners are presumably attached to extra support under Roy's pants.
Continuity mistake: When 51's guys are on the roof of the jail, Johnny sets up the red hose roller with a safety line on the roof edge between the two ladders, but when Roy climbs up the orange ladder to go over the edge, that hose roller with the safety line are not on the roof edge and can be seen still lying on the ground, then it reappears in place in the aerial shot. Additionally, when Roy goes over the roof to make his descent, there's a second silver hose roller at the base of the overhang, which was never actually placed there.
Visible crew/equipment: When Station 51 is dispatched to the plane crash, we hear Captain Stanley respond, "KMG365," and as he walks in front of the engine the partial reflection of the cameraman is visible on the windshield, right in front of Mike who's sitting in the driver's seat.
Audio problem: When Squad 51 is being dispatched to 'man unconscious possible heart attack', this particular view we have of the apparatus bay shows the brick wall where the bay's door track is located on the right of the screen, and we can see that the bay door is up, but when Roy turns on the squad's ignition, we hear audio of the bay door opening even though it's not actually closed.
Visible crew/equipment: When Roy and Johnny load the woman who fainted onto the ambulance, the curly haired attendant gets in the back with Roy and the patient, but en route Roy is alone with the patient, and when Roy tells them to pull over we see the silhouette of the curly haired attendant sitting in the front passenger seat. Then when the ambulance pulls over, only the driver is in the front.
Visible crew/equipment: When Roy's in the ambulance with the woman who fainted, he gets permission from Brackett to leave the TKO patient, so he and John can join Engine 51 at the traffic accident nearby. When the ambulance pulls over, the reflection of array lighting can be seen on the surfaces of both the ambulance and Squad 51.
Continuity mistake: When Squad 51 is dispatched to the possible heart attack, the address given is 11044 Conquistador, but when they arrive at the incident the addresses on the homes are 8042 and 8046.
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 ★