Slicesword’s eyes bored into Harry’s. "The Malfoy Manor wards can be set to deny portkeying out, apparating out and flooing out. The wards can cast something like the Imperturbable Charm on the house itself, so that the building cannot be damaged or penetrated, or its doors unlocked. These abilities of the wards give the Malfoy Head of House another way to stop prisoners in his dungeon from escaping."