Re: AVENGERS: Grade, Reviews, Discuss, DVD & Sequel **SPOILERS**
So I was thinking about the "blow up the mothership, all of the secondary ships and aliens die" trope the movie played out and came to maybe
a reasonable conclusion.
The Chitauri forces appeared to be biological when they removed their masks and such but they all dropped like robotic drones when Iron Man blew up the mothership. I think maybe
it's possible the alien drones/soldiers could have been equipped with a "kill switch" that executes them should contact with the mothership be lost as a way to either deter rogue soldiers or to prevent potentially captured soldiers from being a liability.
Just because it's futuristic doesn't mean it's practical.