Night – The SHREIKING SACK, which despite the name is actually a very quiet suitcase from East London - but that's not the point.
Sirius Black is telling his life story to the trio, unknown to then Snape is cunningly hidden under a mouldy old blanket, both hands over his eyes, invisible to the world.
SB: "…and then they made me their chief!"
DRAMATICALLY Snape flings aside the mouldy blanket and unveils himself. STUNNING everyone inside who hadn't wondered at the door opening and closing ITSELF.
SS: "Fear not! For I shall save you guys!"
HP: "We don't need saving you fool! Everything is perfectly fine."
SS: "You're going to get yourself killed you fool!"
HP: "No, no, no, no, it's quite alright, this has all just been a misunderstanding!"
Harry smiles reassuringly at the ESCAPED CONVICT and the WEREWOLF.
SS: "He's trying to kill you! He broke out of prison to kill you! But don't worry for I shall save you!"
HP: "No, you stupid man he broke out of Azkaban to kill my best friends rat!"
SS: "You fool he killed dozens of people."
HP: "How can you be so dense, Pettigrew blew himself up!"
SS: "SHUT UP! I am here to save you now start grovelling! On your knees, go on, yeah I'm talking to you…"
HP: "No! I shall attack you instead! Haha!"
Harry, Ron and Hermione all attack Snape who hadn't even bothered to DISMARM anyone.
HP: "Now, after dealing with that obviously unstable and highly dangerous man, please continue Mr Black."