come on...tell us the age difference

After that last little note to you, I can't help but think she is playing with you. or else hasn't got the guts to be honest about HER feelings for you. If she doesn't WANT you, she doesn't want you to HELP her. She would become indebted to you, and she would hate that.
I've know quite a few people who continually 'threaten ' to kill themselves...and they are still around

I also knew people who simply disappeared, and were found days or weeks later, in some secluded spot where they knew nobody would try to stop them. Just one example that I posted here just after Christmas. The 26 year-old son of one of Ellie's friends here hanged himself in his bathroom. All alone. The suicide note was totally matter-of-fact, and simply said 'I don't want to live any more. I don't blame anybody, or anything. I just wasn't right for this life'. Even his MUM didn't realise.
And seriously...Does a woman of mature years, who is telling somebody many years (according to you) younger that she wants to die, and then go off on a WOMEN'S Night????
Just as some people like to have power over some poor little puppy, and make its life HELL for 'Fun', there are people like that too. Please...how old IS she? Might make things a lot clearer to understand.
My ultimate opinion is simple. Get away. Leave her to her own devices. It should NOT be your problem, and she is, simply, NOT YOUR PROBLEM.
You owe her nothing any more.
Nick