It always struck me as odd that everyone's favorite house (Slytherin) were seen as not wanting to defend Hogwarts. Despite being sent to the dungeons, later in the movie some of them escaped and fought against Voldemort. Since it was only Pansy Parkinson who entreated someone to grab Harry, why did Professor McGonagoll send all of Slytherin House to the dungeons rather than just her? Answer This is a film thing really. In the books nobody is sent to the dungeons, they're evacuated. '... evacuation will be overseen by Mr Filch and Madam Pomfrey. Prefects, when I give the word, you will organise your house and take your charges, in an orderly fashion, to the evacuation point.' Harry Potter and the Deathly Hallows - p.489 - Bloomsbury - Chapter 31, The Battle of Hogwarts It is expected that most people will evacuate, but not everyone is required to leave. [...] Ernie Macmillan stood up at the Hufflepuff table and shouted, 'And what if we want to stay and fight?'...