As far as revenge goes... destroying a whole city, possibly spreading the infection to the entire world, and infecting people on our team all in one go? I've gotta give that 8 out of 10.

[ grudgingly, but credit where credit is due. if they indeed did this to retaliate... they have to admit it's going well for Zymandis so far. ]

At least this means we know who we're up against... and what we have to do. If we know the virus is of alien origin, at least that's better information than nothing.