This is entirely a question of philosophy, most notably on the discussion of "killing vs let die" as well as violation of non-aggression. Firstly, by severing the connection between yourself and another being that is relying on this connection to live, are you actually "killing" the being, or are you simply "letting it die" by denying it access to your connection? There really is no objective answer to that, as it's entirely a question of your own beliefs. Secondly, and probably more important to the discussion, is the issue of another being that is using your body beyond your consent. Since you no longer consent to this being's direct use of your body, you would again have every right to rid yourself of this now-invasive being, by whatever means necessary.