Revealing mistake: During the rescue of the two mountain climbers who are stuck on the side of a building, when Johnny and Roy are hanging from the lines which are attached to the lifebelts buckled around their waists, we can also see that attached to their lifebelts are carabiners, which are tucked inside their shirts. Those carabiners are presumably attached to extra support under their clothing. Johnny's is particularly visible, while Roy tries to cover his carabiners with his hand.
Revealing mistake: When Station 51 is dispatched to "accident with injuries," en route one of the camera angles is from the POV behind Roy and John, where the back of the squad is located. The problem is that there's bright sunlight on their backs as they’re driving, when it shouldn't be there. Artistic license is acceptable, but having so much sunlight where it should not be reveals that Squad 51 is not in its normal state.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy