Until the end. Yes, Draco's gonna go all Inigo Montoya, without being amusing. He's really angry. I hope that JKR runs with that in the next book instead of ignoring it.

This is Draco's big opportunity to be a Real Boy, er, I mean three dimensional character. She had just better run with it.

And, yes, this wasn't a self-contained novel at all, not like the other books have been. But I hope that all the setup will make the last two books that much better.