The movie had a woman main character, there was a monster or pet of sorts kept behind bars/locked, we never saw how it looks like and only saw it as a POV-shot when it roamed and hunted people, there was red stripes/electric charges flashing on the eyes/screen.

The main character woman accidentally releases it in the very end of the movie and dies, the doctor or main evil character dumps her body in a wooden box to a cave and the movie ends there. There might have been a scene where another woman is running through the forest and goes inside a cabin but the creature finds her there anyway.