Continuity mistake: When Roy and Johnny are on the roof with Harriet, we can see the shadow being cast by the utility pole on the street down below, and when the police car shows up moments later that shadow has changed significantly. (00:12:40)
Continuity mistake: When the guy (Michael Conrad) with the gunshot wound is being wheeled out of the treatment room there is nothing on his face, but in the shot from the hallway as they exit the room suddenly he has a tube inserted into his nostril with tape holding it in place.
Continuity mistake: While Squad 51 is out on the run (quite literally) with the female OD, Johnny gets a cut on his elbow which he keeps fidgeting with even after it's bandaged. When Roy and Johnny get back to the station and see The Old Engine, Johnny's cut has vanished.
Continuity mistake: When Johnny starts chasing Harriet down the street, in Johnny's closeup when he passes the white house (right after the yellow house), there is a light colored wagon-style car parked in the driveway, but in shots from other angles there is a green 2-door parked in that driveway.
Continuity mistake: When the squad rolls up on the OD victim's residence Roy drives the squad over the little fence and bends it. When he takes off the gate is back in its original position.
Continuity mistake: After 17's Captain Harmell has fallen through the warehouse roof, when Roy wraps the tape around Harmell's leg splint, the entire splint is covered by tape when they lift him up the ladder, but when Harmell is carried out of the snorkel, there is much less tape - it's wrapped around the splint only 5-6 times.
Continuity mistake: When 51's guys are at the back of the station with The Old Engine, Johnny tries cranking it and his watch reads 5:20. Then after Squad 51 is dispatched to the heart attack, when Johnny's on the line with Rampart after defibrillating the patient his watch reads 11:15, then after administering atropine, his watch reads 2:30.
Continuity mistake: When Johnny and Roy walk into Councilman Wilby's home, Wilby's wearing a buttoned up shirt and tie, and they place the O2 tank near his feet, but in Wilby's first three closeups the O2 tank is already behind the couch by his head and his shirt is unbuttoned with no tie, but in the wide shots Roy and Johnny haven't even made those changes yet.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy