Who else is gonna work with you with this attitude?"
―Sarah in response to Alex's temper, Entry #9
Our first and only sighting of Sarah in the entries, is in Entry #9, when she, Tim and Seth are acting for Alex's student film in a park gazebo. When the tape cuts in, the four of them have apparently been filming for quite some time that day, but none of the takes have lived up to Alex's standards. His cast are understandably irritated at having to redo the same scene so many times, and they are beginning to lose patience.
While Tim is more ready to make snide remarks to Alex, Sarah attempts to keep things civil for a while longer until Alex snaps at Seth for turning off the camera and for having brought his dog to the shoot and Sarah raises her voice to tell him to calm down. She defends Seth, saying that it was just a mistake, but Alex dismisses her and tells her to memorize her lines. Tim chimes in, mocking Alex for his attitude, pointing out that they're not paid enough to put up with this. When Alex asks him why he should pay them for what they're giving him, Sarah replies that no one else would want to work with him if he's going to be the way he is. Eventually Alex reels himself in enough to start the next take, and the tape cuts out.
Sarah is mentioned again in Entry #22, when Alex informs the camera that he's losing time and that "Everyone is gone."
There is no indication one way or the other about Sarah's current condition, whether she is alive or not.
Marble Hornets, the Film
Sarah is also seen as a central character in Alex's Kralie's student film. She has been cast as the love interest of the protagonist, Brian. According to the trailer, Brian left town after high school and has come back to find that things are not quite how he left them. Sarah is shown saying, "You thought you could just show up and I would be here waiting for you?" When she receives nothing more than blank stares from both Tim and Brian sitting across from her, she drops her head to the table in exasperation.
Later in the trailer, Alex's voice is heard asking Brian why he came back, if it was because of Sarah. Brian answers, "I thought I'd be able to leave her behind along with the rest of this town, but I can't seem to get her out of my head."