|Very effective at throwing the reader into a story. Interesting bit of disorientation which provides incentive for the reader to read on and find out what is happening. This is a very neccesary quality in a mystery/suspense work, which I am assuming this is.
In terms of suggestions, I have a few. I, however, am not in any way shape of form a master writer, so take my suggestions with a grain of salt.
Towards the beginning of the piece you have a slight habit of repeating the focus objects in close succession. For example "pain-induced slumber just as a sharp stab of pain". In this sentence your primary focus is pain, but you probably need to find another adjective to avoid sounding repititious. Her sluggish slumber, disorienting slumber, or a sharp stab of [insert synonym for pain here]. You do a similar repitition with the word finger. It is difficult to describe an object without repeating its name more than once, but it is possible to do through either synonyms or metaphor.
Also, your inner monologing from the character sounds like it is being just a little bit forced, so as to create setting without the author needing to outline it himself. I would suggest re-reading it and trying to find a little bit more subtlety to create a more natural tone of your characters thoughts. Perhaps up the disorientation, have her forget momentarily what Serine is. "Where have I heard that name before?" or something like that.
Great story, I'm interested to know more and I hope that my suggestions only helped and did not in any way discourage or offend.