I said "precipice" on Friday, and I'm not convinced that it wouldn't have been accepted. (It's more reasonable than accepting "zero hour" for the "eleventh hour" clue.)
The phrase "enormous sea-bord cliff" appears only in the preface of the book, "A Pair of Blue Eyes": "One enormous sea-bord cliff in particular figures in the narrative." The cliff itself is also referred to as a precipice and as an escarpment in the text.
The category name doesn't disqualify "precipice", since it's the scenario, not the word, that's a cliché. The best argument against "precipice" is the use of the word "this" that seaborgium pointed out. Hey, I'm just looking for some piece of vegetation to grab onto as the foothold crumbles beneath me. Maybe some bystander can save me using