Have you ever been on a military base? Besides being enormous (Ft Hood is one of Americas largest bases) firearms are tightly controlled - no one is randomly walking around with a gun.
EDIT - I see we crossed posts. You may want to learn a bit more about military bases in general, and Ft. Hood in particular. To reiterate, on a base such as Ft. Hood it is going to take quite some time for armed assistance to arrive, and there is virtually no chance of encountering a concealed carrier - a fact that someone stationed on base would be well aware of.
