Sometimes it is necessary to play detective and ask some good question about what differentiates two seemingly similar situations. If you can rule out panick disorder, then look to environmental factors. Does this happen in only one restaurant?
Do they season with msg (a known neuro exciter)? Are there open flames in the restaurant (natural gas or carbon monoxide? What is different about the restaurant situation/experience? There can be many factors. Ask yourself more questions to get to the bottom of this seemingly perplexing situation. There may be a simple answer.