@Hank you've hit on such an important point here too..actually 2 important points.
One is the need for self-care. If you are in a situation like you have described where you are in the conflict for hours and in some case like you and @soul have highlighted where you are physcially prevented from leaving, you need to look after yourself here. Both in the moment and after the storm has past. Sometimes if things escalate too much we do need to call the police for assistance and while this is not something we want to do and it is a hard thing to do...it is perfectly ok in that moment to do this by way of looking after yourself and others that may be in the situation. Doing something after things have calmed down is also important in order to cope with the emotional exhaustion that follows with conflict of this intensity.
The second is the need to be heard. Your right in saying that at its core...everyone wants to be heard and validated. It is ok to retreat in the moment if this is what you need. You are able to validate and retreat by saying something to the effect of "...I can hear that you are feeling very frustrated right now and I want to talk about this with you, however I dont feel that now is the right time. We can talk about this when we are both in a calmer state of mind...". This way those feelings that have come up for the other person have been acknowledged and you have reflected that they have been heard, but now is not the right time.
