Unlike the other Reviewers,
I reckon you did really well,
Its a great little one shot and it makes you feel for the character (unlike some stories out there).
Its short and sweet and harsh.
Its a story i'll remember

Well done.

Its true. You do have a rather abrupt ending. Perhaps you could better conclude if you described the release from the self inflicted pain and let that bring the tension down.
Also the paragraph were the character enters the room is poorly written. If you have no intention of writing anymore on this you should leave the part about the door out. It takes away from the intensity. I relize your probly trying to use show a chain of thoughts, but that really digresses...

I I I I D I I - your paragraphs speak (first letters).

Reading your story is like riding a missile into a concrete wall. You speed it up, you tease the audience, you keep their attention, and then...you just stop. And you don't stop with a bang. Your devastation module stops right at the barrier and nothing happens. Silence. The hell with that? I was promised fireworks! I was promised a grand finale, climax, culmination point, something!

Writing like this just won't do. If you dare to mock the reader with having a pot of gold, you are going to pay in full before the story ends; you haven't done that at all. I feel insulted and cheated. Seriously, you can never be too sure about a person's style, for I thought better of you as a writer at the beginning than the end.

Below average.

Have a nice, abuse-free day.