some good advice on how to not get pulled into self defense mode would be great.
Keep your mouth shut. I learn this in Db. If something doesn't work, do something different. If trying to put out your side makes this person try harder to see her point of view, just don't say anything. I have a boss who will keep on you if you try to float your point of view. When I keep quiet, she says her peace and is done with it. And then at review time, she tells me I have a great attitude.