I like the idea... but perhaps it could be altered in a few ways.
Maybe dieing / being taken gives you a cooldown of a few minutes? (10 seconds < x < 5 minutes)
Maaaybe.... players revert to the old team after a few minutes? So that you must hurry and get everyone within a time frame?
Maaaaaaaybe.... One team is out to infect, (Like zombies) and the other is trying to hide, but they have to find the "Cure". When they find items to cure the infected, the infected become non-zombie-like again, and are immune. Then you could just add a time limit to this and BAM. New game-mode.
Whatever though, I'll let Greek2me do what he does and expect it to be cool.