Draco knew Hermione had questions too, they danced eagerly behind her brown irises. Dolohov mentioning the cabinet in her presence didn't give Draco any options other than to come clean. Said vanishing cabinet was causing a stir inside him, he decided that once he had talked to Theo about tonight he would find a way to sneak up to the room of requirement and blow it to smithereens, Dumbledore's plan be damned. His bond would not be endangered again because of him. 