How did portia swallow fire?

Portia, a character from Shakespeare's "The Merchant of Venice," does not literally swallow fire. The phrase can be interpreted metaphorically, reflecting her intelligence and determination, particularly in her courtroom speech where she outwits Shylock. If you're referring to a specific performance or adaptation where Portia is depicted as swallowing fire, that would be a creative interpretation rather than a text-based event from the play.