Okay. These will be kind of random.
On formatting, please separate your paragraphs with a space -- double spacing them. I figure this was a matter of cut and paste and all that, but what you've posted is hard to read. It's one big block of text and hard on the eyes. If I find a story like that, I don't want to read it at all, and that's before I've read anything.
First -- dialogue punctuation. That's all wrong. A common line of dialogue is:
"Let's go out tonight," he said.
Note the punctuation: a comma before the close quote, and a lowercase "he" in the dialogue tag, or dialogue attribution. When you have a dialogue like this, there must be a comma before the close quote, not a period, and the pronoun or article should be lower case.
“I need a prescription,” she said, sitting on the edge of his desk. “And I need it bad.”
-- blank line between graphs --
Perplexed, the intern furrowed his brow and stood from his seat. A woman appearing a in a full latex body suit screamed crazy all over it.
You need those periods and commas for everything to flow and make sense. (And you need to delete that extra "a" in the last sentence.)
Another rule of thumb with dialogue is to put dialogue by different characters in their own separate paragraphs.
I also think you're way too flowery in your descriptions. It's good to have a unique turn of phrase, to find a new way to make your stuff pop, but I think you over do it. "With bags of a sleepless life?" What does that mean? And "slipped past him like second-hand smoke?" Not a particularly pleasant image, given that second-hand smoke is a health risk. She may be a risk to his health, but I don't think the image of cancer is quit what you were going for.
I also just don't get Grace, so you do need to develop her character. She's a stalker, fine, but why? And I don't get the stuff with the dean. What does her mother have to do with anything?
For getting Ivan's information, she'd probably just say "off the internet." People can and do hide that info on different sites like Facebook so that's not a guarantee.
I noticed you use smoke imagery throughout, and that's fine, but it doesn't work for me. I associate smoke with health issues, bad teeth, bad breath, etc. Nothing sexy. And she has a figure a smoke stack? Most smoke stacks I've seen are just straight cylindrical columns; I think you're thinking of the big cooling tanks (I think that's what they are) you see at nuclear power plants.
A prescription is not the same thing as a favor, so I don't think Grace's metaphor works.
I feel like you had all these things you wanted in the story and you tossed them in. Mostly they're in the right order and all, but it feels kind of empty and rote. The characters have no heft. Grace is perverted and "without a trace of consent in her"? Again, what does that mean? And why is she like this? Why did she pick Ivan, or anyone else? If she chose Ivan to help with the dean, then why did she bother with the others? Is she a psychopath?
You say this is supposed to be Ivan's fantasy, but so much of it is from Grace's POV. Why isn't it all his? And why does he fantasize about this? Does he imagine he can best her? Does he want to be dominated somehow?
I'm afraid mostly what I have here are questions, not answers, but I hope they help.