When Kathy stops alongside the car with the dead lady inside, it appears as though the window nearest the car is wound down. The next view is from the inside of the victim's car looking at Kathy in her car. But her door window is still up and it has rain droplets on it. It would be difficult to remotely wind down the window of a different cars door.
Kathy rolls down the passenger's-side window of her car to (hopefully) get a better look into the victim's car. The view from inside the victim's car is showing the raindrops on the outside of her window and Kathy's open window.
Kathy rolls down the passenger's-side window of her car to (hopefully) get a better look into the victim's car. The view from inside the victim's car is showing the raindrops on the outside of her window and Kathy's open window.