There is a huge fight breaking out due to inter-floor noise

I live in an older building, and the people on the 8th and 9th floors just had a fight that almost turned into a physical brawl. From the sound of the shouting, it went something like this:
8th Floor: I was willing to put up with normal daily noise. But what you are doing is malicious harassment. What on earth are you doing? Are you literally grinding a ~~saw (I think they meant something like a chainsaw) against the floor? I feel like I'm going to lose my mind.
9th Floor: Haven't we told you several times that it's not us? We all wear slippers. In fact, didn't you install speakers? I looked into it, and that's illegal. I'm going to report you. We are sensible people. You are the one who is mentally ill. You're hearing things. Get rid of those speakers.
They were fighting so loudly that all the neighbors came out and even the security guard showed up, but they kept arguing for a long time before finally going back inside. However, having experienced inter-floor noise conflicts myself, it seems like the noise might be coming from a different unit or a facility rather than the unit directly above. In my case, it wasn't the unit diagonally above, but the one below me lol. But since emotions are already so flared up, it seems they aren't considering that possibility. I'm a bit scared that something might happen.