Well, maybe. Russian myth had a magician who put his life (soul) in an egg to become invulnerable, then hid the egg. Breaking the egg would kill him. Plenty of similar things, usually putting the soul into a finger then cutting it off. I've seen stories of souls/life essences caught in mirrors, photographs, paintings (Dorian Grey, kinda), jars . . . the Egyptians had a multipart soul one part of which stayed in the body. Santaria has a myth that an evil magician can trap your sould and control you.
I never heard of part of a soul bein' taken - maybe that is why I am so confused. Btw, elves do not even have soul in FR - they have spirit... so... bah....
I actually agree with you - plenty of times I played the game "till going to Spellhold" and then abandoned it and still live.
Souls get up to all sorts of wacky highjinx.