Sometimes due to anger people end up showing their weakness. The insecurity and ego flow with the conversation. In such situations, one cannot argue with reason.
We should empathize with the angry person and investigate what could have been the cause for it. The anger and non-rational act should be forgiven.
We humans are generally good, it is a situation and circumstances which gets over us.
A friend of mine also advised that being a great listener when other side is screaming helps.