I've had some less dangerous personal experience with that when I was a little older than she is and it seriously freaked me out.

I worked at a video store near the downtown area of SLC while I was a college student. My shifts were either 12am to 8am or 4pm to 12am. The same creepy guy started to show up in the store near the end of my shift whenever I worked a swing shift. He'd hang out up front and talk to me or follow me around the store if I needed to return videos to the shelves or whatever. It was very awkward.

I'll also add that from my late teens through my early 20s, I was very frequently hit on by gay guys so I became very aware/paranoid of it. With the creepy guy at Movie Buffs, it was obvious that he was into me. A fellow co-worker started to jokingly refer to the guy as my boyfriend.

Anyway, I became very skilled at losing the guy in the store and sneaking out of there before he could follow me into the parking lot. Sometimes, that meant sticking around for as long as half an hour.
Looking back, more than 30 years later, it seems weird that I'd have been so nervous about it. All I needed to do was reject him, right? Well, it felt more intimidating than that at the time.

One night, after I'd slipped passed him and made it out into the dark secluded parking lot, I heard his voice behind him say, "That's a big backseat you have in that car. Do you want to go somewhere?" I turned around and there he was with a creepy look on his face. He stepped over to the back door as if to open it as I told him, "No, I'm just going to go home."

I jumped in the car and drove away.

As far as I know, I never saw the guy again, but it was very creepy and freaked me out.
I imagine it would be much, much worse for a woman than a guy.
I wouldn't be surprised if she chose to quit and walk away from there permanently.