My response when I saw this for the first time a few months ago went pretty much like this: screaming ARE YOU KIDDING ME and gasping for air even though I was sitting on my landlubbing posterior, safe and sound - and dry - at home.
My second response was to google the hell out of it. And, as is made obvious by the people who created the movie, it is fiction - the subject and the camera operator are both champion freedivers, but the 'dive' in the video was, as I understand, composed of several different dives spliced together. The makers of the movie never suggested it was anything else than that, either.
But, you know what? It doesn't matter. It's an amazing clip. Here's the deal: I'll stop writing, and you watch it. Deal? Deal.