Because as much as Draco told himself – and Hermione seemed to believe – that he couldn’t have saved her that day, he could have. All he would have needed to do that day was grab Hermione and disapparate with her when the Snatchers had first brought her, Potter and Weasley to the Manor. But he hadn’t, of course. Why would he have? She had just been another mudblood, albeit one Draco knew.