Again, I don’t think anyone is realistically healing gunshot or stab wounds during a mission. If anything, you might roll to aggravate a flesh wound or injury by fighting, climbing, etc., rather than resting, but the game doesn’t need regular healing to top off hit points when they aren’t drained consistently by each encounter.I think this elides over "how long" and "with what treatment" than is useful in many cases.
But people do. It makes an enormous difference where the gunshots land. And what the guns are. I can say this with personal certainty.
When I said. ‘ I don’t think anyone finds it plausible that their unarmored character can just take gunshots with impunity, so I don’t think they should survive because the rules make gunshots non-lethal,” I did not mean that every gunshot should be lethal. In fact, most gunshots aren’t. But every gunshot has a decent chance of hitting something vital.
You can’t, for instance, charge someone with a gun, safe in the knowledge that the first shot or two can’t stop you. (You can charge and yell and hope they panic and miss, of course.)
It wouldn't be weird if it wasn't all that likely, depending on those factors however. A lot more military using modern body armor survive in environments where they can (and sometimes do) get hit by rifle rounds than was true even a decade ago.
Yes, armor works, and people do survive hits to their armor. And they can die from hits just to the side of their hard armor plate.