What can I do if my boss threatened me?

I work for a security company in Massachusetts, yesterday afternoon one of my co-workers came to me and told me that my boss threatened to throw my down an escalator of a lobby of a cinema in which I was guarding all because I was talking to a maintenance guy that also works on property this isn't the first time he has threatened me. The first time he told me that he “will throw me on to rout 1" (which is a high way) because my wife text me on duty about diapers that was needed for my child. This man swears and curses at everyone mostly all my co- workers can't stand working for him. I confronted him immediately after my co-worker told me about the threat about throwing me down the escalator his word according to three witnesses was "get him out the cinema before I throw him down the escalator". The way he talks to me and other employee he makes you feel like he can snap and hit you at any moment. So when I approached him I recorded our conversation for security purposes and a proof on how he talks to me and other employees. When I asked if he threatened me he denied it and even denied the first threat he did as well I spoke to him about how I feel and I don't want to work in an environment like this he tells me what you want to do I will take your resignation if you like and I said no because I like my Job but I just don't like to be threatened. I have the whole conversation recorded and him telling me to "shut up and sit my ass down" this is how he talks to people what do I do?