The story I heard was the throttle stuck open, and off he went over the cliff.
I had something very similar happen to me when I was in San Francisco area. I was being given a test ride in a 1964 corvette in 1974. The owner was driving us up a very twisty Corte Madera Ave and stopped. He wanted to show me that the engine was real tight and didn't burn any oil. He told me to look out the rear did a rolling start in first gear and then floored it. Everything was fine until we went past redline because the linkage stuck. We luckily went off the side of the road going up the cliff and not the other side. We ended up on the roof in the middle of the road.
The car was a mess but we were ok.
Meanwhile, here on planet Earth...I debate whether or not to sell my beloved 2005 Acura RL. It could easily bring six figures, if you count the 2 after the decimal point.