I think Helena has a hint of an inner Bellatrix inside her, the crazy character she develops in Harry Potter shows a certain familiarity to herself becasue she plays Bellatrix so well. I think Helena being the versatile and amazing actor that she is, she has to have a part of every character she plays for the fact she plays them so well with a sense of nyumbani inside herself, which makes her a believable actor and therefore Lost in the movie.