Movies do help with story structure and character and a few other things, but from reading you also get grammar and word mechanics and sentence flow etc. But yeah, paying attention to how movies work is definitely helpful.
I was thinking of borrowing stuff from other films/books that are regarded as the most brutal and disturbing. For example, in American Psycho(the book), the killer shoves a tube up his victim's genitals and puts a rat in the tube. I think my killer could put a tube in his victim's rectum and he releases fleshing eating rats in the tube I hope it is not too hacky. I thought about being as twisted and disturbing as possible