-Based on the events that happened towards the end of the Half Blood Prince. If you do not wish to be spoiled, I wouldn't read this.-
Always was your Law
Snape gazed angrily down at Dumbledore. Who on earth did he think he was? How could this man, this wizard who Snape respected beyond anyone else, expect him to carry out the promise he had made all those months ago?
Snape had done a lot of stupid things in his life but never…this.
Do it Severus. Please. You know you have to. Remember what we talked about. You must not die, Draco must not die…but I can. You will be more help to Harry in the future than I will. You promised to do exactly as I say. Please, do as I say. Now.
Snape continued to look down at Dumbledore, deep into his eyes and beyond, reading his thoughts. He stared down at him in revulsion.
He was not a murderer.
Sir, I will not do it. I can help you off this tower. Don't ask me to do this.
Severus, you WILL do this. After tonight, I'd be weak anyway. The gap has been too long between drinking the potion I found and finding you. After you have killed me, you can continue to bring down Lord Voldemort from the inside. He will trust you. You know it is the right thing.
How can it be the right thing! I will be hated by every non-death eater in this world! I have told you time and time again over these last few months that I would NOT – DO – IT and I am being very serious. I am not a murderer. I will not use an unforgivable, least of all, the killing curse.
Do it for Lily.
Snape almost collapsed at the sound of that name. Lily Potter or, Evans, as he had known her. The only woman he had ever loved. Would killing Dumbledore please Lily? He thought not. However, her son's safety always came first. Maybe she would have wanted him to do this.
Do you want the death of Draco, an innocent boy, on your conscience? You would be a coward to not do as I say. In years to come, Harry would forgive you for doing the right thing.
I don't care what Potter thinks!
I think you do. I know you do. He has his mother's eyes.
My word is law Severus.
Snape swallowed hard, feeling a cold sweat creep out on his skin. Albus Dumbledore's word was always law. It always had been ever since Snape had found out that he had accidentally sent the Potters to their death. Since then, Snape had done everything Dumbledore told him, hoping for some kind of redemption.
He stared down at Dumbledore in utter revulsion once again, hating him for asking him to do this, hating this clever man for making him think it was right.
Always was your law, always will be. I will bring down Voldemort for you Sir. Goodbye.
Snape watched the green light send Dumbledore careering over the tower and out of sight. Out of the corner of his eye he saw the gathered Death Eaters smiling in delight and Draco standing silent and shell-shocked.
He didn't even want to look at Harry. Thank god his face was invisible.
For of course, he knew Harry was there against that wall. He had spotted the barely visible feet underneath the cloak minutes before. He felt a surge of anger. Once again, because of this boy's existence, people had been killed.
Lily and now Dumbledore.
He would never forgive Harry.
A few minutes later, he heard the 'chosen one' call him a coward. Him! A COWARD? How dare Harry Potter call him a coward after what he had just done! How can killing one of the most powerful wizards in the world, by request, be cowardly?
By killing the last person in this world who had ever cared about him, Snape considered it to be the most un-cowardly thing he had ever done.
For who was going to defend him now?
-As you can see, I am quite the conspiracy theorist.-