WARNING: This page is about a different car, the 2003 Pontiac Montana, 2003 Oldsmobile Silhouette, and 2003 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
Use J 38778
in order to remove the door/opening carpet retainers from the carpet retainer.
Fig 1: Removing Door/Opening Carpet Retainers From Carpet Retainer