Continuity mistake: During the structure fire at Kiddytime Toy Factory, when the man is downed by an electrical shock, Johnny pulls out the defibrillator and Biophone from the squad, and in Johnny's closeups with the Datascope we can see that its center knob on the right is missing, but in the Datascope's closeups the knob is back.
Continuity mistake: When 51's guys go down into the tank to try and subdue Al, the big guy who has a chemically induced psychosis, the ring Al was wearing on his left hand in the overhead shots is gone, but when Al shakes Chet upside-down in the closeups the large ring is back, but then it vanishes again.
Continuity mistake: When Station 51 is at the scene of the oil well eruption, underneath a house which was built atop an abandoned oil field, just after Johnny tells Roy that he thinks the whole foundation is slipping, it cuts to a shot of the front porch as one of the porch columns (and part of another) breaks and falls. However, when the guys finally free the trapped man and carry him out, all the columns are upright once again.
Continuity mistake: While Roy and Johnny are under the house with the oil eruption trying to free the trapped man, they get covered in black oil and mud even though they're wearing turnout coats. It drips down their necks and their pants are soaked with it. When they get to Rampart with the victim, Roy says that he and John should get washed up, but when they talk to Dixie they haven't just washed up, their clothes are now impossibly spotless.
Continuity mistake: While the boy who has cyanide poisoning is in the ER, Dixie looks through his clothing and finds carved peach pits, and when she directs Brackett's attention to all the carved pits, the items change when it cuts to the closeup. Additionally, that closeup starts out being farther, and we can see that Dixie is not beside the table before it zooms in.
Continuity mistake: When Station 51 is being dispatched to the fire and explosion at Martell Industries, the other companies called are Station 36 and Engine 14, but we see Engine 236 at the scene even though they were not called. This is before Captain Stanley asks dispatch for the second alarm.
Continuity mistake: During the fire at Martell Industries, when Roy and Johnny make a mad dash out of the building before the explosions, and midway Roy's helmet falls to the ground as he keeps running, but in the next shot when he and Johnny reach the engine and dive to the ground, the helmet is hanging around Roy's neck.
Continuity mistake: During the fire at the chemical plant, the distinctively marked SCBA tanks that Captain Stanley, Johnny and Roy are wearing, when they're searching for the missing man, change when they're inside and then finally exit. Note the different stickers, or lack of stickers, on their tanks.
Continuity mistake: When Johnny and Roy are treating the officer, while hiding between the bakery truck and car, the sniper fires at them which leaves multiple bullet holes on the side of the truck. However, when Vince talks to the Sergeant on the handie-talkie and then fires the tear gas, all the bullet holes on the truck are gone, but they soon reappear.
Continuity mistake: At the lion pit, when John loads the photographer onto the stokes he places the yellow blanket package under her head, and as Captain Stanley, Marco, and Roy lift the stokes out of the pit, we can see that the package is under her head the opposite way.
Continuity mistake: When Dixie gives John a tetanus shot because he fell from a skateboard onto cactus, we know they're all in treatment 1, because when Johnny and Roy are at the open door we can see the door and wall (with fire extinguisher) on the opposite side of the hall, but in the next shot from the hallway he and Roy are leaving treatment 4, which is opposite treatment 3.
Continuity mistake: After the sniper throws the rifle out the window, Captain Stanley gives the orders over the HT to Engine 12, Truck 23 and Engine 23, and the next few shots of the rigs are from previous episodes including 3x7, "Promotion", when Roy and John rescue the security guard at the structure fire.