This is an old movie from last year.
It seems to me like the video was shot to show this happening.
It could be the case then that the X200 was 'made' to come off for the video.
But, that doesn't mean it didn't happen originally through operator error or defective component(s) and the video was shot to highlight that.
One could think that it was shot and posted to discredit SureFire. I suspect that people seeing the video who have a clue about firearms and weapon-mounted light would draw the same conclusion this thread has so far - most likely operator error (if I'm reading the posts correctly).
I feel it is important to point out that SureFire improved the X200 to prevent this sort of thing.
Along with other improvements the latch spring was strengthened:
Old version on the left.
Current version on the right.
The X200A & X200B come standard with the latch mount and the even more secure RailLock mount:
If your X200A is the old version and it is not mounting as securely to your firearm as you would like, I am pretty sure that SureFire will take care of you if you call them and explain your situation.
Al