Quote from : Harry Potter and the Half-Blood Prince Movie

Bellatrix Lestrange: [walking into the astronomy tower followed by Death Eaters] Well look what we have here. Dumbledore wandless, alone and cornered in his own castle! Well done, Draco!
Albus Dumbledore: Good evening, Bellatrix. I think introductions are in order.
Bellatrix Lestrange: Love to, Albus, but I'm afraid we're on a bit of a tight schedule.
[to Draco]
Bellatrix Lestrange: Do it!
Fenrir Greyback: He doesn't have the stomach, like his father. Let me finish him in my own way.
Bellatrix Lestrange: No! The Dark Lord was clear, the boy's to do it.