Um...restraining order??

Seriously though, this guy seems to be on the path of taking this to the extreme, if you are starting to feel unsafe, you need to start a paper trail. How is a piece of paper going to protect you? It's not, but a paper trail can ultimately make him accountable for his actions in the long run.
Do you have any mutual friends, could one of them try to calm him down? He seems to be on an emotional high, and may need someone to talk him down from it, otherwise he may not think clearly and take things to the next level.