That's really evil. They know they can't say something like that. And actually, what's so sad about it is, they don't really care about you and they never did. The one thing that drives this guy to say something like this is he's thinking about all the paperwork he's going to have to do and he knows he's going to have some explaining to do with the CO. I figure the CO probably holds elders responsible to some degree. It's easier for him to try to manipulate you back in than it will be for him to face the music when you finally leave.
Ultimately, it's just words. They can't actually kill you, it's just empty threats. There's a good chance he doesn't believe any of it anyway.