♥!The Young Adult Book Club!♥ discussion

I have an assignment for my creative writing class: i have to write a movie script and I have no idea how to end it.
Its about a girl- Jenna- who goes to a writing institute for a vacation to improve her writing. Her writing supervisor- ester- turns out to be very creepy.
In the past we know that jenna's parents were victims of a house fire
We learn that jenna is in a mental institute and that Esther is her nurse.
In the end i want the viewer to think: maybe jenna is not crazy after all, maybe ester id indeed the psycho bug i cant figure out how to do that in the last scene.
Thanks for ur help!!

Maybe you could show Ester doing some psycho stuff to other people with Jenna to witness it all.