1. Dumbledore's Big Chill
Harry and Dumbledore are up on the top of the tower underneath the Dark Mark. Harry is wearing his invisibility cloak, Dumbledore ordered him to put it on before they mounted their brooms to ride to the top of the tower. Harry hears footsteps and looks around, but Dumbledore orders him with a gesture to retreat. Harry draws his wand and backs away:
The door burst open and somebody erupted through it and shouted, "Expelliarmus!" Harry's body became instantly rigid and immobile, and he felt himself fall back against the tower wall, propped like an unsteady statue, unable to move or speak.(HBP pg 584)
It's interesting to note that things are happening so fast, even Harry is momentarily confused:
He could not understand how it happened -- Expelliarmus was not a Freezing Charm -- Then, by the light of the Mark, he saw Dumbledore's wand flying in an arc over the edge of the ramparts and understood... Dumbledore had wordlessly immobilzed Harry, and the second he had taken to perform this spell had cost him the chance of defending himself. (HBP pg 584)
Why did Dumbledore freeze Harry? Harry was already invisible to their attackers and in no danger. The only explanation could be that Dumbledore already knew, had already planned, that he would die this night (or appear to die), and not only did he not want Harry to become involved and possibly be injured himself, he needed Harry to be a witness, to be able to tell everyone else what happened.
Dumbledore might have also promised Snape that he would make sure that Harry would not be able to interfere, knowing how Harry feels about Snape and what Snape was about to have to do. The supposition that it was Dumbledore's plan to do this all along is supported by the fact that he acted so quickly to do it, almost without thinking, when Draco burst in on the scene. Harry's own assumption that the Freezing Charm was done by Dumbledore is supported by the fact the curse lifted when Dumbledore left the tower minutes later.
The door burst open and somebody erupted through it and shouted, "Expelliarmus!" Harry's body became instantly rigid and immobile, and he felt himself fall back against the tower wall, propped like an unsteady statue, unable to move or speak.(HBP pg 584)
It's interesting to note that things are happening so fast, even Harry is momentarily confused:
He could not understand how it happened -- Expelliarmus was not a Freezing Charm -- Then, by the light of the Mark, he saw Dumbledore's wand flying in an arc over the edge of the ramparts and understood... Dumbledore had wordlessly immobilzed Harry, and the second he had taken to perform this spell had cost him the chance of defending himself. (HBP pg 584)
Why did Dumbledore freeze Harry? Harry was already invisible to their attackers and in no danger. The only explanation could be that Dumbledore already knew, had already planned, that he would die this night (or appear to die), and not only did he not want Harry to become involved and possibly be injured himself, he needed Harry to be a witness, to be able to tell everyone else what happened.
Dumbledore might have also promised Snape that he would make sure that Harry would not be able to interfere, knowing how Harry feels about Snape and what Snape was about to have to do. The supposition that it was Dumbledore's plan to do this all along is supported by the fact that he acted so quickly to do it, almost without thinking, when Draco burst in on the scene. Harry's own assumption that the Freezing Charm was done by Dumbledore is supported by the fact the curse lifted when Dumbledore left the tower minutes later.