Vehicle Suddenly Shuts Off?

I'm not sure if this is a common problem.

While driving, I accidentally hit the keys in the ignition with my right knee and all of a sudden my TL shuts off. But the key was still in the "start" position. Luckily, no cars were near me. As a result, I put the car in "Park" and turned the car off. Then I was able to restart the car again, and off I go.

Has anyone had this problem before?