HPB: The proof of repentance

[pippin_999]

"YOU
HAVEN'T"
Harry 
yelled.
"YOU'VE
GOT
THE
WRONG
MAN!"
*
GREAT
BIG
THUMPING
SPOILER
AHEAD
DON'T
READ
ANY
FURTHER
IF
YOU
HAVEN'T FINISHED...
I TELL YOU ONCE,
I TELL YOU TWICE,
WHAT  I TELL YOU THREE TIMES
IS TRUE.

>>Dumbledore's eyes were closed; but for the strange angle 
of his arms and legs, he might have been sleeping. Harry 
reached out, straightened the half-moon spectacles upon 
the crooked nose, and wiped a trickle
of blood from the mouth with his own sleeve.<<

Okay, there are not one but three things in that paragraph
that don't fit with AK. The trickle of blood, the  closed eyes,
and the peaceful expression. Cedric's eyes were open, so were 
Sirius's, and they died looking surprised. The Riddle family died 
"Lying there with their eyes wide open!" and "a look of terror"
on their faces. And that, needless to say, was all that was wrong.
No blood, of course. Avada Kedavra leaves no sign.

So the AK didn't kill Dumbledore. But if we're to trust Bella,
the AK is itself proof of the intention to kill. That is, it's 
Unforgivable because it doesn't work unless you really mean
it. Unless you're prepared to take the life of a Being with the
same cold-blooded indifference with which Fake!Moody 
dispatched the spiders and Wormtail killed the spare, the
curse will fail. 

The question is, though, if you do intend to
kill, can you block it from succeeding if it's performed
correctly otherwise? I don't think you can.

If Snape meant Dumbledore to die, either from the fall or
the poison, I don't think he could have kept the curse from
working. And it's obvious that it didn't work. 

Now maybe Dumbledore thought he could save himself,
and maybe he did, or maybe that part of the plan went
rather spectacularly pear-shaped -- time will tell.
But what we saw is the final proof of Dumbledore's 
trust in Snape -- he knew the curse wouldn't kill him,
because Snape was no longer a murderer.

I think Dumbledore withheld the proof of Snape's
repentance because it *was* proof. It would leave
absolutely no doubt in Harry's mind -- or
Voldemort's-- that Snape was faithful.
As Harry is no Occlumens and never will be, that
would be very bad news for Snape.

There is only one guaranteed proof of loyalty. Snape
must have summoned Fawkes. As Dumbledore
says in CoS, only someone who showed him
real loyalty could do that. And notice how Fawkes
sang out in HPB when Harry pledged his loyalty
to Dumbledore again.

Pippin