Hatchback/liftgate problems of the 2000 Oldsmobile Silhouette

I was driving my 2 children (ages 3 and 5) and my brother in my 2000 Oldsmobile Silhouette. I was traveling at 40 mph. With absolutely no warning, my van lost all power. I tried several times to put on my hazard warning flashers but they would not work. I put my van in park and turned off the ignition. We tried to exit through the front doors and through the passenger side rear door but all three doors were locked and would not open even after pressing the unlock power door locks several times. I attempted to open the rear hatch but was unable to do so. I managed to crawl over my 3 year old who was in a full size car seat next to the driver side rear door. After feeling around in the dark, I finally found a door handle that would open.