So apparently, some researches modified an E.Coli bacteria to add two more dna codez.
So, imagine if they're in the middle of it, and suddenly a war starts and because the first thing the military guys do is bomb funny looking buildings, they accidentally bomb a research facility which was doing genetic experiment with highly resistant bacteria or whatever.
And then, the explosion, because it's warm, helps the research synthetical life forms to mutate in random ways as they fly over the place, getting into the air, soil and the water.
Then the nearby population starts to get sick over being infected by these randomly spread synthetic bacteria.
Zombies? Mutants?
What if the bacteria, besides being synthetic also were /programmed/ by the resarchers? Because nanobots are expensive.
And then you get a gray goo of mutated bacteria.
Pretty cool story, eh?