I'm no NiN fan but a friend is and he showed it to me, maybe in about 1995 or 1996?
I don't remember much about it, but it wasn't added in accidentally - there was some story about how NiN had some sort of big to-do with their record company about including it in the video.
And it was definitely fake. It looked fake, for one thing... and I think if it were real there would have been a public outcry and media blitz as big as the one going on around Michael Pedophile Jackson today.
Check out Snopes on the subject of
snuff films.
That doesn't mean you weren't close to being hack-and-slashed, just that the movie was a fake. Hope that helps you sleep better.