"La Revanche des mortes vivantes" has been released in two different versions. An Erotic Version and a shorter Horror Version with an alternate ending. In the Erotic Version, it's pretty obvious that the girls just faked their deaths to rip off a company to get money. They dressed up as zombies to perform the necessary homicides. These scenes are missing in the Horror Version. That's why it seems as if the car with the zombies goes up in flames.