Lossing car key at office parking lot ... right after I arrived the office parking lot

So it was a normal work day morning. I woke up, took showed and then drive to work, found a parking space, and left the car.

Fun started after I closed the car door, about to close the door with my car key, and found that the car key was gone.

Ridiculous. The car key must be around, since I USED IT TO DRIVE HERE! I looked around, check my jacket, looked into my backpack, inside out upside down. 30 minutes passed, and I still couldn't find my car key! Then suddenly I remember that I have a tiny LED flashlight in my backpak. So I yanked it out, and used it to check underneath the car. Still nothing.

Finally, I checked underneath the area underneath the driving seat ONCE AGAIN (tried before), and there it was the car key at the corner.

At least I found it eventually, but I am still puzzled how it got there, consider that it the time because I turned off the engine of my car and stood outside of the car was merely 5 seconds.