Why Lily didn't have to die

[Marianne S.]

No: HPFGUIDX 137613

Tonks_op:
I am beginning to think that Lily did not have to die because she was 
a potions master in the same class as Flamel.  Maybe LV had a lab set 
up with Snape and he wanted/needed someone else to help with the 
experiments.  This is sort of like RL when the enemy kidnaps the best 
scientist to make the better weapon.  In this case LV may have wanted 
them to work on making the philosopher's stone.  He could then use 
that as a the ultimate Horcrox. 
 
What do you all think?

Marianne S:
I think that's an astute theory/analogy. I wonder if it even has anything
to do with the "three times" Harry's parents had defied Voldemort.
I believe that Snape is perfectly aware of Lily's potion skills and would 
be more likely to use that as reasoning to Voldemort to still spare Lily's
life, because I believe Snape would know that  Voldemort wouldn't have
been swayed by whatever love Snape had for Lily.

Consequently, even though Snape knows that L.V. believes Love is a 
useless emotion, it is probably his feelings for Lily and anger at Voldemort
that caused him to have the iron-clad remorse. 

I wonder, however, about using a philosopher's stone, or anything else
that would have to be in use, as a horcrux. One has to get an "elixer of
life" from the stone which means it would have to be touched. Does that
offer enough protection of a horcrux to satisfy Voldemort? This makes
me wonder about Nagini. We know Dumbledore believes her to be a
horcrux, but Wormtail also has to "milk" her venom during GoF. Would
L.V. have made her a horcrux after that fact? Can a horcrux be a horcrux 
and still do its other "duties" (such as Nagini attacking Arthur Weasley 
or can one drink from a cup in which there is a Horcrux). We know that
Ginny couldn't write in the diary without being possessed by it, so maybe 
the poisonous nature of Nagini is that horcrux's own protection. 

Am I writing in circles?

Marianne S