remove the window roller handle and door latch handle (interior), then take something stiff and skinny (I used a butter knife) and gently pry the clips from the door.
they are a U shaped, so if you can slide the butter knife up to where you are pushing on the panel clip and not the door panel it will not rip the carboard.
kind of hard to describe with words. but if you saw the clip you could see that there is a two pronged end that goes into the door, and a curved U shape that slides into the door panel.