2018 Subaru Legacy Brakes Problems

My wife experienced an unintended acceleration in her 2018 Subaru Legacy. My wife had begun to slowly back out of a parking space in a school parking lot when her 2018 Legacy went into an unintended rapid acceleration in reverse. The car took off in reverse and did not respond to her applying the brakes. Somehow she managed to steer the car which was rapidly acceleration in reverse, virtually uncontrollable, and guide the car down a row of parked cars until she clipped the front of another car at the end of the row and her car came to a stop. Thank God there were no students in the parking lot at the time! The floor mats in our Legacy are Subaru mats that lie flat and in no way would affect the accelerator pedal. As the car was accelerating in reverse, and she had removed her foot from the accelerator onto the brake, the brakes did not slow the car. There is considerable damage to the right rear of the car and trunk. After the accident, when the car was restarted, the accelerator and brakes worked fine and she was able to drive it home from the scene. Thank god students were not in the parking lot! [XXX] [XXX] (cell) [XXX] Nashua, NH 03062 (May-Oct), Ponte Vedra, FL (Nov-April) INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

CAR WAS AT A TURNING INTERSECTION. CAR WAS COMPLETELY STOPPED, FOOT WAS APPLIED TO BRAKE WITH NORMAL PRESSURE. WITHIN A FEW SECONDS, CAR STARTED TO PROGRESS FORWARD, I LIFTED FOOT OFF BRAKE AND REAPPLIED. THE BRAKE DID NOT SENSE PRESSURE, I PUT THE CAR IN PARK. THESE ACTIONS DID NOT STOP THE CAR. LAST EFFORT ATTEMPT WAS TO LIFT THE EMERGENCY BRAKE APPLIED. THIS STOPPED THE CAR. I TURN OFF THE ENGINE AND RESTARTED THE CAR.