Though our silence be drawn from us with cars, yet peace. It's clear that Fabian wants to Sir Toby and Sir Andrew to hold their peace, but the way he puts it is odd. "Cars" means "chariots," and Shakespeare usually uses the word "car" to refer to the chariot of the sun-god. Also, we think that speech, not silence, is "drawn" from a person, as when someone is tortured. Maybe Fabian is being witty, or maybe the excitement of the moment made him twist his words.