I recall one of the Bungie crew saying there was an Easter Egg in the H3 loading screen that hadn't been found yet (I think it was in a mailbag last year). This seems likely to be it - I haven't watched the video with the sound on, but the subtitle makes it look like he's actually using the thumbsticks to zoom out, rather than it just snapping in and out of its own accord, which adds weight to that idea.