How did she ...Spoiler?

Had Ella been a doll, she probably would've killed all the families already way before the time of this movie at the rate she was going. All the families were killed earlier so why didn't she finish the job?

If not:

What I don't understand is how all the families died in the first place where mary and her dolls were buried already. How could the early families scream if they are not in the same room with a doll that made them scream?