Herman called his mother, but before she came out of the house he ran to get a better look. Do I need to set off the prepositional phrase before she came out of the house with commas? Herman called his mother, but, before she came out of the

I was taught that prepositional phrases were essentially "expendable" components of a sentence that, while referring to the subject-predicate, are 'not really there.' In the context of the following sentence the author uses a