2015 Subaru Outback Seat Belts Problems

I was slowing pulling into a parking space and just straightening out the car when I heard a strange sound coming from the engine. Immediately after that I heard a very loud engine revving sound and then suddenly the vehicle shot forward like a rocket, went over the cement barrier and into the wall of a building. It seemed like a very high rate of speed, though the distance was only about 8 feet.

SUBSTANTIAL RUST HAS DEVELOPED AT THE ATTACH POINT OF THE DRIVER'S SEAT-BELT TO THE DRIVER'S SEAT AND OF THE ATTACH-POINT OF THE DRIVER'S SEAT TO THE CAR. WE'RE THE ORIGINAL OWNER AND THE CAR WAS NEVER FLOODED OR EXPOSED TO WATER IN ANY OTHER WAY. I TOOK IT TO THE DEALER TWO WEEKS AGO AND THEY DIDN'T KNOW WHAT TO MAKE OF IT OR DO ABOUT IT. THEY REACHED OUT TO SUBARU AND (AS OF 4/24) THE DEALER HASN'T RECEIVED A RESPONSE. THE PASSENGER SIDE DOESN'T HAVE THIS PROBLEM, BUT THE DESIGN IS ENTIRELY DIFFERENT -- NO EXPOSED METAL. INTERESTINGLY, WHEN THE SERVICE ADVISOR CHECKED OTHER LATER-YEAR GEN 5 OUTBACKS THE DESIGN HAD CHANGED: THERE WAS NO LONGER ANY EXPOSED METAL IN THE EQUIVALENT LOCATION. THE NEWER DESIGN FOR THE DRIVER-SIDE ATTACH-POINT MIMICS THE PASSENGER SIDE - NO EXPOSED METAL. A 2016 OUTBACK IN FOR SERVICE HAD THE SAME EXPOSED METAL DESIGN ON THE DRIVER-SIDE SEAT. IT ALSO HAD RUSTING AT THE SAME LOCATION (ALTHOUGH NOT NEARLY AS SEVERE AS ON MINE). IT DOES NOT SEEM SAFE TO HAVE THIS KIND OF RUST AT SUCH A KEY ATTACH-POINT FOR THE SEAT AND A CRITICAL SAFETY DEVICE LIKE A SEATBELT. WE LIVE IN A WARM/TEMPERATE PART OF CALIFORNIA AND THE CAR HAS ALWAYS BEEN "HOMED" IN PART OF CALIFORNIA, SO IT HAS NOT BEEN EXPOSED TO HARSH WEATHER.