Great thread Rowan!
I have 'walked away' for a moment or more, too. It really helps me to get myself back in balance.
I went through an uncomfortable experience on the weekend. We were invited out for dinner by our real estate agent and her husband to thank us for using her,and she invited another couple (who introduced her to us). She brought up the 'What do you want - white or red?' the moment we sat down. Husband and I both politely declined and said we'd order Diet Coke, thanks. This wasn't acceptable and she and her husband both jumped on us. I was at the point where I was one second away from walking out of the restaurant. Then she said "But, you can't drink Diet Coke, we're celebrating" and my husband said "Just watch me". Boy did she stop talking!
I have found that stepping into the washroom for a moment alone works really well for me. It brings me back to reality.