I do love the idea of semi-public sex, and the chance of discovery, of which these two seem so blithely unconcerned. I really like the details in this--the half-hidden parchment on the wall, the grille at the top of the elevator, that lucious line of hair on Snape's belly. Yeah, I'll weigh in as one of the manacle crowd--OH YUM. The best part is that Harry looks so different here, no trace of canon here.
Everyone's right--it's begging for fic...just so we know how long they're in that damned lift!