Continuity mistake: When Station 51 is dispatched to the 'unconscious female in a car' it's 8:20, but when Roy is on the Biophone with Rampart his watch reads 11:05, and John's watch reads 12:30 as he's checking the woman.
Continuity mistake: On the roof at the studio, Wally sets up John's gear and anchors his rappelling line onto a single carabiner which is attached directly to the belt support around John's waist. Yet when Johnny flips upside down while rappelling down, in the closeups when Roy joins him, that carabiner is now locked off onto another carabiner, which is attached to John's belt, and both of their locking mechanisms are red. Then when John's on the ground, the carabiner attached to his belt and anchor is entirely silver.
Continuity mistake: When Roy and John are at the studio so John can test out Wally's rappelling gear, on the roof John's wearing his medical holster, but Roy is not, but when each rappel down in the wide shots they're both wearing it. Then in their closeups while hanging on their lines, Roy's wearing his medical holster, but Johnny's has vanished, then on the ground Johnny's wearing his and Roy's has vanished.
Continuity mistake: At the studio, when Roy and Johnny are on the roof with Wally to test out Wally's rappelling gear, before Johnny rappels down the thin swami around Johnny's waist and the loop at the back are both green, but once he rappels down the swami belt is grey and the loop is blue.
Continuity mistake: When John and Roy rappel down together after John's rope kinked up, as they reach the bottom Roy and John remove their helmets, but as Wally rappels down both paramedics still have their helmets on in the overhead shot.
Continuity mistake: After watching Brice's interview on TV, all the guys sit down at the table to eat dinner, and there is one jar of mustard on the table. When Roy smears mustard on his bun, Chet motions for the mustard with his eyes and Roy slides it over to him to use, but in the next few shots the open jar of mustard is either in front of Roy or Chet, depending on the angle of the shot. The milk container keeps switching places as well.
Continuity mistake: While Brackett and Morton are working on the boy who was shot with a pellet gun, when Morton is about to intubate the boy, we see that the O2 mask has been removed from his face and lying behind the boy's head, but when Morton hooks up the hose to the ventilator, we see the O2 mask and its elastic are still around the boy's neck. Then when Brackett says, "Prep him," the mask is gone.
Continuity mistake: When Johnny and Roy are in the staff lounge waiting for Dr. Morton, Johnny's holding the newspaper's sports page, and in the page's close-up, there is a large picture of Brice centered between two columns of articles. However, when Johnny's talking to Roy and Dr. Morton, that page is entirely different even though he hasn't turned the page.
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 ★