Wow....What a twist...I don't know what to say...Only thing I could said is that Snape is ruining himself and their relationship bit by bit, and I don't think Draco is really want to rescue/love Harry. To me, he is more like: someone have have something very precious but didn't know to keep it, and Draco know their value and slip in and take it away when they are not aware~ And I feel he think he is better suit to Harry than Severus, so he just use this situation to take Harry away, because Snape and Harry's relationship is so easy to break right now, why not just take what he want?
Now I really want to know what Harry feels about this?