The Green Goo Again, and a new(!) view of the Tower (long)

[pippin_999]

No: HPFGUIDX 165765

::Pippin does forehead slap::

Bet you a butterbeer I know why Dumbledore seemed to know so much about
that nasty green potion in the cave -- he knew  the guy who 
invented it. Not Voldemort, of course, but the erstwhile ESE!Snape.

That explains *everything*. Snape could have told Dumbledore all about 
it when he defected. Dumbledore could then recognize  it from Snape's 
description, do that little spell only to confirm that this was indeed the 
nasty stuff Severus had told him about, and know immediately 
what he could and couldn't do.

He could also know that it will take some time to kill him and that 
Severus keeps the antidote prepared, just in case. 

That would be why he wants Snape and *only* Snape to attend to him. It
would also mean that Dumbledore made the decision to die rather
than get help at the moment when he froze Harry. It had nothing 
to do with the vow, IMO. It had to do with not outing DDM!Snape. 

Yes, maybe JohnWayne!Snape could have saved Dumbledore. But with DE's
in the castle, Draco and Harry as eyewitnesses, with Rosmerta already
aware that Dumbledore was dangerously ill, Snape couldn't have done 
it without revealing his true allegiance. And if he did, then vow or 
no vow, the one  'who I believe has left me forever' would be *dead*.  
If the vow didn't kill him, Voldemort would. The vow is really a 
beautiful piece of misdirection on JKR's part, to make us forget that
if Snape reveals himself as Dumbledore's man he's going to be dead
anyway.

Does it make military sense for the commander to sacrifice himself for
the genius? I don't know. But I know the US defeated Japan despite losing
FDR. I'm not so sure it could have done without Einstein and 
Oppenheimer.

But wait, there's more <g>

If we allow any legilimency between Dumbledore and Snape, then
Dumbledore could easily tell Snape what had happened -- even if
Dumbledore hasn't mastered Voldemort's trick of inserting entirely
imaginary conversations into other people's minds, Dumbledore 
need only visualize the potion's name in writing for Snape to see it.

Snape can know there's little chance of saving Dumbledore now. 
And he can know that he was in a way the instrument of 
Dumbledore's death.

Thus the look of hatred and revulsion as he prepares the ruse that
will preserve Dumbledore from Fenrir and preserve the illusion of
ESE!Snape.

Snape doesn't mind being called a coward for not fighting. He's
following Dumbledore's orders and getting the DE's out of the castle
before they can do any more harm. But he screams "DON'T" when
Harry calls him a killer, and then follows up with "CALL ME A COWARD!"
which hides the real reason for his anguish. He is by no means
a coward. He is leaving his friend, Dumbledore, to face death alone,
so that he can obey his friend's last wish and save Draco who
has rejected him, and Harry whom he despises.

So ::takes deep breath:: even if Dumbledore died of the poison,  
 Snape may have killed Dumbledore, or at least contributed 
materially to the means of his death.

If Snape invented the potion and Dumbledore died of it, we get a 
whole tragedy of sin coming home to roost without losing
the reality of Snape's attempt to redeem himself. 

Pippin