Youre not and mythbusters kinda proved this. They shot a ball at 50km/h in one direction while driving in the other, also at 50km/h. The ball stayed in place because they were no longer in contact and their frame of reference is no longer the same and they deal with their own resistances and speed. This means that yes, the diver would lag behind. Maybe not as far as in the comic, depending on car speed, but he would be behind the spot he left on