Hey, it sounds as though your friend is going through a rough time and her homicidal thoughts can be linked to mental health issues. I'd advise you to keep close contact with her and inform a trusted adult. She needs some serious help.
However, homicidal thoughts are quite common, in teenagers, but that doesn't mean to say you should just leave her. You said that she hates living and plans to be dead in two years or so, this may be due to depression, in which case, ask her to see a counsellor, or tell a trusted adult to refer her.
Go to this website for more understand and information.
You may also like to check out this link, and pass on some of the information to her.
This thread has loads of advice on what she can do, in the mean time.
Good luck.
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