How does a radical muslim get into the Army?

The short answer is they don't. This is still one more bit of proof that islam is a religion of evil. Their satanic verses tell them to kill or enslave all infidels, you and me included. When people finally wake up to that fact, we can start solving the problem.
I do not advocate killing them all. What we need to do though is take scum like Nidal Malik Hasan and execute them in a way that is against islam. Take this scum bucket, tie him to a post inside of a pen. Turn hogs into the pen. slaughter the hogs, and pour the blood over him. Force morsels cut from the hogs down his throat. Then take bullets, dip them in the pig blood and shoot him with them. Finally, dig a pit, toss half of the hog parts in, toss him in, then the rest of the hogs. Then let wild dogs consume the pile.
Film the entire thing, and broadcast the vids on Al Jazeeras frequency all over the arab world. As far as I'm concerned, do the same thing to every prisoner at GITMO as well.