Today on the bus home I started to wonder about the possibility of Snape dying to save Draco -- he's half roped into it already, but there's a powerful message to the readership in that -- in that he remains ambiguoous, but vaguely noble,, but more importantly, in the face of all the Gryffindor loyalty-rah-rah-rah, it sort of shows that loyalty can have a lot of other weird shapes. I bet if it happens though we'll still never know why he's close to that family in spite of it all (since none of them were years mates).