God dammit - this is stupid, but I feel compelled to prove myself. Try as I might, though, I can't recreate this. I can make the gap itself (and I will upload a video with the gap and a bailed flatground flip to prove hardcore) but I can't land it. I guess it was a landing glitch of some sort.
Funkyfunction, it is hardcore mode. I wouldn't have a way to prove it to you, though. I don't play on normal or easy, which is why this gap is so hard to get. Every time I'd tried it before, IF (very big if) I was able to clear the stairs, I'd bail immediately.
Tell you what - go try it a couple of times on HC and get back to me.