Do you think zombies can catch a cold...if so, how about any other disease? The Vx seems pretty tight, mine has close to 120K miles, now I have the stereo in it, not a vibration outside. That is very impressive, still tight after 8 years. My 07 Expedition sounds like aluminum cans rattling around and I have about the same system.
So with that said, what would it take to make it self contained? I am thinkin submarine style, get some CO2 scrubbers, weld the passenger door shut as well as the rear door, put an airlock on the drivers side....wait, I almost forgot, we have to seal the street sweeper turret on the roof. Not sure about that one, how did they do it in star wars?