(at around 14 mins) When Mike and Carl are pursuing the "Student Driver" car , in long shots, only blue lights are visible on the roof of the police car, while in close-ups of Mike and Carl, red and blue lights can be seen reflecting off the roof. Also in long shots, the grill lights are on in some, off in others. They aren't really on the road. These are done with a green screen so the footage of the police car is not the same as the prop car they are in.
In this episode Molly's Melissa McCarthy shoe size is 8. But in season 1 episode 12, "First Christmas", Molly's shoe size is said to be 61\2. This isn't a goof. Shoe sizes vary greatly depending on where they are made.