Does she say what why she want to kill/die? What is the reason? BTW for "her" to write "through you" she does not need her to take control over you body. You need to just sit in front of a blank page, EMPTY YOUR MIND and write all that comes without stopping.

It anyways is YOU regardless if takes care of your body or not.

I had what seems as my male alter pressure / influence me from within - to throw myself under the train (said it would be great freedom to have the body torn apart and released, and also claiming that another could bring it back to pieces afterwards...and that i will not really remember or feel anything)

Later i made a group gathering, to estimate a situation from recent flash backs and tried to occupy him and do things that he would do. I did that and felt very happy and familiar with something old that was gone. Maye try to ask her why, what she wants, etc.