This footage purports to be of a U.S. Army special forces sniper on assignment in an undisclosed location. (As to why the soldier responsible for this acquisition would consider the location's revelation to be too risky to reveal, while simultaneously putting his job and/or life on the line by simply providing me with it… well, who can say?)
Still, it's not enough for any sort of conclusion to be reached. The video starts to die too soon, and then the audio follows. With the truncated condition of the clip, it's tough to tell who our real American hero is protecting us from… be it a hushed virus strain re-animating the dead (as it clearly suggests), or merely some ridiculous actor in the tattered remains of a hospital gown. Either way a faint notion exists that leaves the viewer questioning can this be taken at face value? Perhaps, but it would appear we're being provided with a look into a covered up incident...
Technology in digital video has developed to the extent that any film student with delusions of Orson Welles, possessing the proper tools and a modicum of talent, can create a passable clip such as this while getting drunk in a dorm room.
If the video IS legit, however — and given the look of things at the video's end - the audio's not the only thing "going dead."