I am not a Biologist, but I am a Medical Doctor. And the point that Nei would die when Neifirst dies, has always bothered me, long before my interest in medicine. (who knows maybe it subconsciously influenced me.)
Its just strange. I dont know of any organism that follows this concept.
Here is the example of a Planarian worm, (which I totally chose as the example because it reminds me of the Planar Armour in PSIII, which is the strongest.)
https://en.wikipedia.org/wiki/Planarian#Regeneration
If split in two, it regenerates into a whole organism--each split part does this. But if one dies, the other goes on living, not dying.
There are several more example of cases like this in organisms, or cases of asexual reproduction. For these reasons, it would make more sense that Nei would not die.
Thoughts?