That sex opening made me cringe so hard! Gah. I agree openings scenes with too much potential to be disorienting do themselves a great disservice. I also agree with Serria that I can imagine a "fake beginning" that really pulls it off, but probably something more like your scrapped scene than such a standard device like a dream or flashback. Like most "rules" of writing, I suppose, there are always exceptions that work. You can break the rules if you break them well enough, right? The trouble is knowing whether you're doing it well enough :D