How would you deal with this bad boss issue?

I work in a large building with many unrelated offices. While at my desk today, I could hear someone in an office down the hall shouting at one of his employees. He was cursing and screaming. It is totally none of my business, however, it was that kind of thing that were I at home I might call the police about. It was pretty intense. What would you do? He stopped screaming before I really felt like I had to interfere, but my inaction is also leaving me slightly uneasy.