I would err on the side of caution and call the Police - I have had her mindstate, there was no intervention and I tried to end my life and came so close to succeeding - 5 day coma, nearly passed many times. She is being explicit about her intentions and I would take her seriously. She can be forced to take hospital care - that saves people's lives every day.

If she survives and has a resentment against you, so be it. It's a life-saving situation.

Don't worry about her relationship with the woman - she can sort out her sexuality when she is well enough - it's the last thing to be worrying about it right now.