What is the meaning of diving under the table in the following text?

He was holding a sheet of paper with small print front and back. "This is a promissory note on a line of credit at the Gulf Bank, " he announced, and more than one lawyer considered diving under the table.



The statement is a humorous one. It means that two or more lawyers, having heard the the statement about the promissory note, basically wanted to make themselves as invisible as possible.

I would have to know the context to understand why they felt this way.