My wife and I stopped to get our mail at our community HOA mailboxes. I was driving. I stopped, set/engaged the brake hold button while my wife got the mail. She was about to get back in and suddenly the car lurched forward very rapidly and crashed into the neighborhood playground and the chain linked fence. I could not stop the acceleration and had to keep forcefully applying the brakes and the vehicle finally quit. I was able to steer to avoid some kids playing basketball. I could have injured my wife or others, it could have been very tragic. The 3 boys got out of the way and helped us afterwards picking up the car debris left all around. The damage happened very quickly. I felt such shock afterwards and trauma wondering what happened and what could have happened. The police did a report and took pictures, our insurance declared it a total loss. We have contacted Toyota and are waiting for someone to inspect it before it is hauled away. No warnings prior, the vehicle has worked well. As I managed to drive it home, we noticed a machanical error code after the fact.