OOPS!
neat to see a sidewinder fire after hitting the ground!
We had an incident close to that at RAF Leuchars in Scotland about 20 years ago.
They had just fitted the last of a set to a Phantom when they turned away there was a loud click, a thud, and a loud woosh. The missile had fallen off the wing, hit the ground, and went off.
Fortunately it only travelled about half a mile, and buried itself in the River Eden which flows just outside the perimeter fence.
I believe the paperwork alone, took about two years to complete.