Other mistake: At the end of the episode, when 51's guys are in the kitchen waiting to see the "terrific idea", in the closeup John presses the tape recorder's third white button to play it, and we hear the dispatcher's voice, but in the next shot we continue to hear the dispatcher saying, "1305 Overland Ave, apt C, cross street, Pacific..." despite the fact that we can see all the white buttons are now up, none are actually depressed.
Other mistake: When the woman from the salon is brought into the treatment room she's unconscious, but as they transfer her from the ambulance stretcher to the hospital gurney, she lifts her left arm from under the stretcher bar and then also positions it on the gurney.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy