Dumbledore and Snape again.

[Constance Vigilance]

No: HPFGUIDX 137297

> houyhnhnm:
> 
> When Snape arrives on the tower, he is faced with a weakened 
powerless
> Dumbledore, four mature Death Eaters, and one teenage Death Eater. 
> Had Snape refused to kill Dumbledore, there could have been only one
> outcome.  Snape would die.  Dumbledore would be killed by one of the
> other Death Eaters. Draco would either be killed on the spot or
taken
> back to Voldemort (I suspect the DEs had orders to kill him on the
> spot if he failed.)  The DEs, including, Fenrir would be loosed upon
> the school and the casualties could have been much, much worse than
> they were.

CV:

Not necessarily. See my post just previous to yours. The four DE's 
arrive at the tower while Draco is waffling. Greyback starts to kill 
Dumbledore but is stopped by the unnamed DE. There is no retribution 
taken by either of the other two because of him stopping the killing 
of Dumbledore. 

Then Snape arrives. He AK's Dumbledore (or does he?) and isn't
stopped 
by the unnamed DE. Why is Snape's attack different from Greyback's?

I feel strongly that the unnamed DE and Snape are in cahoots as
double 
agents and that Snape never killed Dumbledore. There is a loophole in 
the Unbreakable Vow, IMO. There is no deadline for taking action. He 
is required to save Draco, which he does. But as long as he 
keeps "intending to get around to killing Dumbledore", he hasn't 
broken the Vow. But there is some reason why it is important for
Harry 
and everybody else to believe that Dumbledore is dead.

~ Constance Vigilance