Continuity mistake: When the guy who was injured in the manhole is brought into the ER, Dix tells them to bring him to treatment 6 (which is around the corner from the other treatment rooms, and has no color lines that run past its door), then we see him wheeled into treatment 6 in the shot from the hallway. However, in the next shot from inside the treatment room we can see they're not in treatment 6, but actually in treatment 1, note the red, green, and yellow lines on the hallway floor in front of its doorway, and treatment 6 has no color lines that run past its doorway.
Continuity mistake: When the TV catches fire in the kitchen, Captain Stanley unplugs it, and when it cuts to Roy running into the kitchen with the fire extinguisher, he passes Marco, who just ran into the apparatus bay. All of this while we hear Cap's voice telling Marco, who already ran out, to get the asbestos blanket. Then, in the next shot, Marco is still standing behind Captain Stanley in the kitchen.
Continuity mistake: Immediately before the man rescued from the sewer fire is brought into the hospital, the shot shows squad 51 and two ambulances in all three spots in the ambulance bay, however neither ambulance is the big box Mayfair type that was at the rescue scene. (00:11:20)
Continuity mistake: When Johnny's on the phone with Uncle Ernie about the new color TV, in the wide shot Johnny writes down the address of the warehouse, and puts the pen back in his shirt pocket. Then Johnny thanks Uncle Ernie, and when he hangs up the phone, in the next closeup the pen is back in Johnny's hand.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy