Sorry, pal, but I see it ending badly regardless.

I recently got involved with a suicidal woman who was quite manipulative, though not as much as your gf.

However, I can tell you one thing with supreme confidence. You need to get outta there, and stay out. Whatever you say you will do ... you MUST do. You must show no fear. This is tough, I know, because you were with this person for 2 years. But, at this point, the relationship has already been compromised, so you need to treat this as a life/death situation for YOU.

Your first priority is to get out safe and sound. This is the tough part ... even if she does hurt herself, you need to be able to tell yourself that you were not responsible for that. Sounds cold, but no, it's entirely practical ... that's all you have at this point. You cannot turn this into a win-win for you and your gf. Your gf is not going to win this one, regardless of what happens. You can come out with your health and sanity intact. Do it.