In addition to collecting as many unique items as I can, late (late) in this most recent run of Fallout 3, I've been trying to get at least one sample of each kind of weapon and armor. It's not like I'm running off a list (as I am with the uniques), but if I know of something that I don't have, well, I want it.
One of those items is the Rivet City Security Uniform.
Now the obvious answer is to just whack one of the guards. And I would -- I have, in fact tried it, sneaking (fully hidden) and with a one-shot-kill weapon (MPLX Megasurge). I specifically tried to whack the guard outside Rivet City, as he seemed to be the most "exposed."
However, his compatriots (including the officer in charge of handing out water with Broken Steel) still turned red and, as soon as I stopped sneaking, opened fire.
I don't want Rivet City mad at me (at least, not until I commit mass murder), so what's the safest way to go about getting me some of that sweet, sweet Security Uniform goodness until then?