2011 LEXUS CT Steering Problems

. ON THURSDAY, 11/7/13, I GOT INTO MY CAR TO GO TO WORK AND THE DASHBOARD GAUGE INDICATED THAT AIR PRESSURE IN ONE OF MY TIRES WAS LOW. I LOOKED BUT THEY APPEARED TO BE OK. I HEADED TO MY MECHANIC INTENDING TO STOP THERE ON THE WAY TO WORK. THE CAR PERFORMED NORMALLY ON THE STREETS AND THE HIGHWAY. MY FOOT WAS ON THE BRAKE AS I ENTERED THE EXPRESSWAY DECELERATION LANE TO EXIT, CAR STILL FINE. I PROCEEDED DOWN THE EXIT RAMP, MY FOOT NEVER LEAVING THE BRAKE PEDAL, I APPLIED A BIT MORE PRESSURE TO THE BRAKE WHICH INITIATED A "FLAT TIRE" , BUMPY SORT OF RIDE. I SLOWLY KEPT BRAKING ON THE EXIT RAMP WHEN THE CAR SUDDENLY ACCELERATED, MADE A 90 DEGREE TURN TO THE RIGHT, STRAIGHT INTO A RETAINING WALL, THE CAR WENT UP THE WALL (OFFICER SAID THERE WAS A MARK ON THE...