Complex sentence: The office space, which used to be a closet, is too small to operate in, and water pipes run through it so they can hear the toilets flush from the Dunder Mifflin bathrooms above them.
Split into simpler sentences: The office space, which used to be a closet, is too small to operate in. Water pipes run through it, so they can hear the toilets flush from the Dunder Mifflin bathrooms above them.