Well, you have the added damage from MoS potentially. Also, the standard damage rules assume that the weapon might or might not be hitting a vital area. The degree of abstraction does make somethings a tad difficult as a result. A solid hit from pretty much anything short of a support or heavy weapon is probably not going to instantly kill you—but you stand to fail a consciousness check, bleed check, et cetera, and even in a best case scenario you'll still be stunned. In other words, much like real life, getting shot once really isn't likely to kill you instantly, but you will be taken out of the fight and may succumb to your wounds aren't quickly and properly treated.
The Hit Locations optional rule captures this better, and the Expanded Hit Locations rule from the Companion ever more so.