Thank you for the clarify. I am tired so I did misread that at first. So he was upset and then chasing you to go on and on and on and on about it?
The situation was more like "Do not feed the bear" then rather than "do not poke the bear?" Still engaging with bear somehow.
Could you walk away and still do the same? Validate and disengage? Like...
"I see you upset. I will not push this or discuss this at this time. Please let me know when you are less upset if you are willing to talk and sort this out calmly. I will back off now."
And go somewhere else?
He could go on and on and on to argue with the air if he felt like it. But you
don't have to be there with someone who is in "bear mode."