2016 LEXUS RX350 Electronic Stability Control Esc Problems

I WILL GIVE YOU A BRIEF DESCRIPTION AS TO WHAT OCCURRED. I ENTERED OUR GARAGE FOR THE PURPOSE OF BACKING THE LEXUS OUT OF THE GARAGE SO WE COULD LOAD NEWLY PURCHASED PATIO FURNITURE INTO THE GARAGE. I ENTERED THE LEXUS, APPLIED THE BRAKE PEDDLE TO START THE AUTOMOBILE. ONCE THE AUTO WAS STARTED, KEEPING MY FOOT ON THE BRAKE TO ALLOW MY SHIFTING, I MOVE THE SHIFT LEVER FROM PARK TO REVERSE AND TO MY SURPRISE, THE CAR BEGAN MOVING WITH NEVER REMOVING MY FOOT FROM THE BRAKE. IT IS A VERY TIGHT SQUEEZE BACKING OUT OF OUR GARAGE SO WHEN THE CAR STARTED MOVING, I PRESSED MORE FIRMLY ON THE BRAKE TO SLOW THE PROGRESS AND THERE WAS NO RESPONSE. I PRESSED ON THE BRAKE HARDER AND WHEN IT KEPT CONTINUING TO NOT RESPOND, I TRIED TO LOCATE THE EMERGENCY BRAKING SYSTEM BY PUSHING WITH MY LEFT FOOT...