Deliberate mistake: Rampart's ER is located in the south lower wing of the hospital complex and it is only a two-storey building (with a basement), but the elevator, which is located past the nurses' station at the wing's far south end, has two floor indicator panels listing eight floors - one panel over the elevator doors and another we see every time the elevator doors open, which is not possible.
Deliberate mistake: After Johnny's and Captain Stone's efforts, when the construction site's cardiac arrest is wheeled into Rampart, the problem is twofold; First, we hear Roy's voice saying, "Full arrest, number four," even though Roy is not actually on this run (that line is from S4xE21 "Back-Up", when they wheel the cardiac arrest into treatment 1, after defibbing him atop Engine 51). And second, the attendant pulling the stretcher changes, and the EKG monitor lying on the patient is the old blue Datascope 850 from earlier seasons (this shot is from S4xE7 "Daisy's Pick", the hypothermic victim - note his wrapped foot!), whereas at the construction site and when he's wheeled into the treatment room, the EKG monitor is the newer white Datascope M/D2.
Deliberate mistake: At the station, Gage is washing dishes and talking about his idea for a new poker game. In this shot the camera is positioned behind the kitchen's top/lower cabinets and sink, facing Gage. The fact that we can see the back side of the cabinetry (paper towel dispenser which hangs over sink is gone) ruins the illusion of this POV from the wall that should be there.
Deliberate mistake: When Roy and Johnny are on the Coast Guard helicopter, approaching Catalina Island with the injured diver, there is a closeup shot of them looking out the windows, which is a flipped shot - note the backwards paramedic patch on the right sleeve, instead of being on the left sleeve.
Deliberate mistake: At the market, after the tiger knocks over the pyramid of Hi-C cans, which were set up blocking the aisle just for that purpose, the officer tells Les, "Down that aisle," and the next shot of the aisle is a flipped shot - note the backwards words on the upside-down boxes. Two shots later that same aisle is shown properly, not flipped.
Deliberate mistake: During the rescue of the car at the top of the draw bridge, The Boat approaches and radios in to say that they have a diver standing by. Then after Johnny shouts, "Are you all right?" the rescue boat is shown again, but this time it's a flipped shot - note that everything is reversed from the prior shot.
Deliberate mistake: While Squad 51 is chasing after Bill, who's slumped over in the saddle on the run-away horse, one of the shots of Bill from inside the squad is a flipped shot. Note the landscape, as well as the shadow being cast on Bill's right instead of his left.
Deliberate mistake: After Roy and Johnny rescue the man trapped under his house, when the ambulance reaches Rampart, in the shot from inside the ambulance when Roy follows the stretcher out, he stops at the receiving doors and waits for John, who just arrived in the squad, and in this semi-closeup, it's odd and very apparent that it's not actually Randolph Mantooth, it's his double meeting Roy at the door.
Deliberate mistake: When Johnny and Roy are on the Coast Guard copter, responding to 'victim down at cliffs at Catalina Island', there are four closeups of the guys looking out the windows which are flipped shots - note their uniforms are backwards, the paramedic patches are on their right sleeves instead of their left.
Deliberate mistake: When O'Brien shows up at the nurses' station for Dixie's answer, after she declines the offer Dixie walks off to a patient who's brought in by the police, and the last closeup that's shown of O'Brien is flipped - note his hair is parted the opposite way and the background is backwards.
Deliberate mistake: After the fireworks begin exploding at the warehouse fire, when Captain Stanley and Roy are helping Willy out, they are knocked to the ground by an explosion, and in two of the following exterior shots the large sign that reads "Kiddytime Toy Co" is visible. This shot is from season 4, episode "The Screenwriter", when the guys respond to the fire at the toy factory that also made fireworks.