Daisy's Pick Blind Date - S4-E7
Other mistake: When Squad 51 is dispatched to "man needs assistance", in the exterior shot as the squad rolls out of the apparatus bay we can see Engine 51 still inside the bay, but the real Station 127's engine is parked right beside the station house.
Daisy's Pick Blind Date - S4-E7
Other mistake: When dispatched to the fire in the theater, the companies called are Station 51, Engine 85, and Station 36, but at the scene of the fire we see Engine 9 roll up and also see firemen with 19 on their helmets. These are shots from previous episodes including 3x7, "Promotion", when Roy and John rescue the security guard at the structure fire.
Daisy's Pick Blind Date - S4-E7
Other mistake: When Johnny and Roy are in the ice house, there's a closeup of Johnny's arms as he's hosing down the ice and removing it from the hypothermic victim's arm, but it's obvious that the dark hairy arms belong to the stunt double, not to Johnny.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy