Runaway master

Obtaining the pass
You can't go into the Upper New Ark without a pass. But where to find one? Well, you can buy one on the black market in the Slums. By this point, you're likely already know the guy who sells junk; well, he also sells various counterfeit passes, each one costing you $100. If he doesn't sell you the pass, go see the hobo who asks for food until he tells you about the pass.

Which one of them would work is always random, and since they take away the pass every time you go past the security post, it may be different one the next time. If they bust you, they would fine you for additional $250, and still take away the pass. There's one-time event if you previously finished the Serial pervert quest, but otherwise there's no reason to get caught.

Fixing the pass
If you want to just make genuinely-looking pass and to not take any risks, you need to pay for another massage session with Lin-Lin; after finishing, she would reveal what your passes are too glaringly fake to work, but she knows someone who may correct them just enough to make it through: the local tattoo master.

Tattoo master would require another $500 for his work, but would make the job done.

From now on, you can create additional passes by yourself, by buying them in the Slums, and then, by tinkering with them via Ink Pen, correcting them to resemble the genuine pass. Be careful, though: in order to do so, you must pass the Nimble skill check, with difficulty of 15+(3*Nim)%. If you fail, the pass would be hopelessly ruined; on low Nimble, it may be more cost-efficient to just pay the tattoo master after all.

Entering inside
Now, when everything is in order, you may go into the UNA. Be sure what the following conditions are met:
 * You are not aroused;
 * You are not armed with weapons;
 * You are not dressed inappropriately.

Otherwise, you wouldn't make it inside.

Finding Fawn
Where is the best way to find a schoolgirl? Of course, in her school, or, in this case, a college. Fawn can be found in the cafeteria on the first floor; approach her when you are ready.

You can either try to talk with her delicately, or cut her no slack and just publicly call her "Master". After that, you can either pretend what it was a joke, and let Fawn guess by herself what it's in her best interest to play along, or continue humiliating her.

After the scene is over, Fawn would go outside with you, to discuss what just happened; her reaction would change depending on wether you acted nice from the start, called her "master" but then pretended it was a joke, or went full-meanie on her, but subsequent scenes would be the same regardless.

Since you have no place to stay, Fawn would allow you to spend one night at her house, which would result in you two having a first night of love. Afterwards, Fawn would return to her condo, and resume her normal schedule.