I don't think you could say he prevented any injuries by doing this exercise alone. I mean, I can squat all I want, but that isn't going to prevent any sort of quad injury or injury to my posterior chain if I deadlift. I know people who can deadlift over 600 pounds who still don't know what they're doing. I know a marine, a cop, two guys in the navy, a powerlifter, and a bodybuilder who all spew out incorrect information from time to time too. I guess if you want to call it an isometric strength training exercise though, more power too you. I just hope nobody else attempts this because they could end up injuring themselves very badly.
Forgot to include the link :P
If you look at how he is doing this exercise, he doesn't seem to be using his neck to complete it. Any sort of isolation exercise for the neck should be completed by the neck ONLY with the head being the point where resistance (if any) is. You should not be moving your entire body. If he was moving only his head an flexing his neck that'd be one thing. Moving your entire body is a different matter. If you'll click on the link below, you will see that neck exercises SIMILAR to this do exist, but are only completed via neck flexation/extension or roatation. But the fact that he is using his body to press and not his neck only doesn't really make this a neck exercise. I'm not saying the record is invalid, I'm just saying that this is a dangerous movement even for a professional athelete.