If you think generals are rational professionals, you should consider reading about what kind of dumb shit they did in WW2 for various stupid reasons. There is a reason the USA has 2 air forces.
You assume the generals would disobey? What if he just replaces them? Why shouldn't he, if they really do that? Russia has some smarter generals, they attacked Ukraine.
True. But the facehuggers incapacitated the people, how are they supposed to enjoy the ride?