When you have the brilliant idea of having your cast members climb under a table/through a doorway, pay attention to the fact that some of your cast may be too tall to fit comfortably under your table.
Joe (aka "Tall Cop" from Episode 6) was very understanding, even though he got stuck at least once and scraped his knee several times.
Also, make sure you cast awesome people (Like JOE!) who won't freak out when they realize they are really too tall to fit under your table, but will keep trying anyway.
Take after take after take.