I was going to suggest that you do exactly what ColdEthyl suggested.
I'd add that if you think telling her you will leave would cause her to immediately turn the rage up to 11, skip that part.
Stand up and say "I'm going home." And walk out and go home.
knowing her she would rage within the restaurant. she has no shame when she is triggered. Therefore I try to ride it out and calm it down without saying so. Saying so would throw fuel on the fire. Been there dun that... Thanks for responding. I appreciate it...
Let her do that.
If you've already gone, it isn't your problem.