This sounds like the beginning of a really great story!

First off, I love your summary. Quite attention-grabbing.

Next, you have a really firm grasp on description. As early as teh first paragraph, I could picture the scene perfectly. I could feel the chill and wetness, and relate to the burning sensation in my lungs.

Your main character sounds interesting. The reader can learn a lot about him/her through the narration, so good move chosing first person.

And lastly, the pace sounds good. You started off with a bit of action and slowly introduced things about the situation and character along the way. Plus you left the reader in the dark and made them wonder why he/she is in such a horrible situation.

On some more constructive notes, though your sentences flow well, some were a bit long and could do with some shortening. When they become too long too often, the narration comes across as rambling. Also, there were several times that you starting with a verb, as in "Turning the corner I..." where I think you needed a comma (I'm a bit comma happy, though, so don't hold me to that ^^;).

Also, [Damn cobblestones, they may look] I'm pretty sure that's a period.

Like I said, though, this is off to a great start! You have a very good narration style and a firm grasp on your plot and characters. I hope you decide to continue this, and good luck with it if you do! :D