Call the police.

Suicide threats ALWAYS need to be taken seriously. If someone is threatening suicide, you don't try to reason with them, you don't try to fix them yourselves. This is a matter for professionals and for professionals only. They are the only ones trained to handle this sort of situation.

I know this sounds harsh, but it is what it is. As someone who was suicidal in the past, I wholeheartedly agree that when someone threatens suicide that its hospital time.

Because if you don't?

They may end up dead and you'll always think "why didn't I do more?"