Seriously though, the 20th level badass in d20 modern can fall to a first level guy's lucky hit. When you take damage greater than your constitution you have to make a Fort Save or drop. Now anyone can blow a Fort save (and I was one typo away from a totally different kind of save . . . ), and the fact that a 9mm does 2d6 damage means that the security guard with the light pistol is actually kind of a threat. Especially with a critical hit, which would deal out an average of 14 damage.
So it's possible to get dropped. It just ain't at all likely, unlike SR where I can shut down most characters with relative ease just by piling on the right combination of recoil compensation, smartlinks and EX rounds
Of course, burst fire from a G3 does 4d10 damage base so it ain't like d20 Modern is that safe either . . . .