Draco had raised his wand only one other time in his life with the intent to kill. It was Dumbledore, that night on the tower. Aunt Bella told him he had to  mean the killing curse. He wouldn't have been able to kill Dumbledore even if he tried, because his words alone weren't enough. When he raised his wand this time, it moved on its own volition, channeling the chasm of red, hellish energy straight to its target. It shocked him, how easy it was. Mumbling the curse into the cold air, he finally understood what it took. He meant it with every fiber of his being as he slashed the second curse at Orion, simply, effortlessly. 