I'm sorry this happened to you jc2. Can you tell us more about the escalation and how you validated?
I'd like to second what
once removed said. Validating insincerely will not be authentic and the pwBPD will feel like you are just trying to get them to be quiet.
One thing I ran into when I first began trying to validate is that I thought I was validating, but I also was being invlalidatig at the same time. Our workshop
Don't Be Invalidating might help you too.