Update 3 - What really happened...

I have been contemplating what happened at the door that we never got to see with our own eyes. First, if the door opens from the outside, Barak never barks or charges towards it. We fixed that behaviour-problem long ago. By all means, we have small kids running in and out all the time! He walks up to it - but - as he now saw a person that he did not recognise, he was immediately alerted. Simultaneously, the woman saw the dog. In this situation she panicked and backed up, trying to escape and close the door. This in turn, triggered the prey drive in Barak, who realised that something was wrong and therefore took action. He charged at her, barked and snapped, and then he backed off, as we approached the scene. In whatever way I toss and turn the matter, I still think that he did the right thing.