Ari at some point opens the door to the shark girl´s room, but her other purpose is to watch over you incase you are to low on the stress meter. If it gets dangerously low, she will invade your office to check up on you, and if you dont fix it she will get you.
Thanks for clearing that up for me. While hunting for her jumpscare, I always died to zero sanity well before seeing Ari. At least on night 1, I went almost the entire night at low sanity before seeing her show up at my room, which explains why I didn't chance upon it.
