Well, for These occasions I have a "DefCon salad" made from smoked garlic, fresh onions and canned tuna... take a bite and take a deeep breath... these People back off pretty soon (sometimes even the rest of the compartment) - and they dont argue with you! Because they want you to keep your mouth shut ^^.
My gf once said, after I ate my defence salad, I smell like a rotting waste bin left in the summer heat XD
Every time.