I was on break and a co worker came in asking how I was I told the co worker the same and asked the co worker as well and the co worker has always been nice to me. And then another co worker came in had something to say to this other co worker it escalated to yelling I was worried I was about to get in the middle of a fight (had nothing to do with me)it was between them both and the entire time I had my head down looking at my phone. But the co worker I had talked to threatened to knock this fellow co-worker's head off. Then when the co worker questioned the first co-worker on what had been said the first I could tell play it off. Should I do anything?
I wouldn't worry too much about what happened. If a member of Mgmt asks you what happened tell the truth, "Knock your block off" I wouldn't take as a eminent promise of physical harm, its more of a "I'm going to stand up for myself".