[He...has no idea what to say or think now, and it's obvious. There is a bewildered, tear-stained boy blinking at Severus Snape. But when he's ordered to get off this ship, his eyes narrow slightly.]

I'll get off the ship when I'm good and ready to get off this ship. There's something I'm here to do. And I won't get that done rotting in Azkaban, even if I do escape.