Grace is a meteor?!
It's the law that all ventilation shafts be at least large enough to fit a single Adam Jensen in them. Granted, secret facilities that ignore the law might not care about that, but such laws have resulted in the standardization of materials, so they generally wind up being able to fight 1-2 Adam Jensens anyway.
(Incidentally, Adam Jensen is the protagonist of Deus Ex: Human Revolution)