It sounds like you have a latch that has gone bad. Don't know of any specific procedure to deal with this. If I had to try anything I would have someone pull the door handle while I laid in the back seat and kicked the door in the area of the latch. There is a chance that this could force a latch that was close to opening. Of course you'd want to take steps to prevent damge to the door panel and be prepared to repair it once opened. Keep us posted I love to hear how this one turns out.