I think your solution is a good one! I think many W&A games are sort of designed with the sort of 'aesthetic' of an abrupt and tragic end, but that's not really going to suit the storyteller in some people. I personally love dragging in oracles for that sort of thing, so I might pull out one of my tarot decks and try to apply 1-3 randomly drawn cards to influence the ending.
When I played The Sealed Library my solution was to have my character fully aware that his doom was upon him and left it open to interpretation what death, precisely, he ended up succumbing to. Based on the way my story ended, he had at least 4 possible things that were going to kill him, even if the game itself dictated a specific one. I also left the door open for him to have saved himself, though my character didn't seem to think it was likely. This seemed to satisfy my storyteller needs.
If you'd like to see a different take on it, in my game Bluebeard's Castle, knocking over the tower lead to an end-game phase called "The Eleventh Hour" where your character reaches a crisis point and has one last chance to save themselves. I was trying to replicate the feeling of the end of the fairytale, so if you're playing a game where a possible Eleventh Hour rescue is possible, it may be something to port over.