Dumbledore's Death was planned

[Arlene]

No: HPFGUIDX 148802

In light of PJ and Tammy's "argument" preciously which were good 
and extensive so I did not list it here. 

Instead I propose my own question / theory.

I belive DD did in fact have that night planned. I always wondered 
why DD did not just "Accio" his wand to save his life??? It was 
right there. 

Which coincidentally, what happened to it in death, don't they 
usually break the wand of a powerful wizard when he dies? (So it 
doesn't fall into the wrong hands). There was no mention of DD wand 
at all.

He repeatedly asked for Harry to fetch Snape. It had to be Snape.

He stopped Harry from intervening by freezing him.

Then he "dropped" his wand and did not retrieve it. (He had enough 
strength to stand there and talk to Draco for a while.)

If anything was not expected at the tower that night, I'd say it was 
confronting Draco.

"Arlene"