Shardblades should be cutting off body parts way more often

So I get they don't cut living flesh. But it's also said that when they pass through the spine, they kill instantly. If I were to swing a shardblade through someone's midsection, I'd likely hit their arm after passing through the main torso. By that point it would be considered dead flesh as much as if I'd pulled it free of their body and came back for their arm, no? So wouldn't there be lots of one-armed corpses? Not even to mention other bodyparts it may encounter in similar fashion?

Edit:

Yes I know it would be gruesome and Brandon likely wouldn't want that happening, just like he wouldn't want cheese to stop shardblades. However, he also made a whole series of systems to explain why shardblades don't cut live flesh to begin with so I thought this would be an entertaining discussion.

I'm quite sure it's been explicitly stated that severing the spine with a shardblade is akin to cutting through their brain, and kills the victim instantly. I'm also quite sure there's an example of a shardbearer immediately passing their blade back through a body they just killed to some extent, and it did in fact cut.

I think the most valid reason I've seen is: "It likely takes a moment for the soul to fully leave" or an argument to that extent about intent, with the body still being seen as one body, however I'm not sure how much intent plays into whether the flesh is alive, it feels rather binary and we haven't seen intent impact whether something dies before