Sirius Black: Brilliant, Snape - once again you've put your keen and penetrating mind to the task and as usual come to the wrong conclusion. Now if you'll excuse us, Remus and I have some unfinished business to attend to.
Professor Snape: [raises his wand at Black] Give me a reason. I beg you.
Professor Lupin: Severus, don't be a fool...
Sirius Black: He can't help it. It's habit by now.
Professor Lupin: Sirius, be quiet!
Sirius Black: Be quiet yourself, Remus!
Professor Snape: Listen to you two, quarrelling like an old married couple.
Sirius Black: Why don't you run along and play with your chemistry set?
Professor Snape: [puts his wand to Black's throat] I could do it, you know... But why deny the Dementors? They're so longing to see you.
Professor Snape: Do I detect a flicker of fear? Ah, yes. The Dementor's Kiss. One can only imagine what that must be like to endure. It's said to be nearly unbearable to witness, but I'll do my best.