Something just hit me (pncchtt! ) the other day. Luke has dragged his dad through the Death Star, and stops at a shuttle. Anakin/Vader tells him to "help [him] take this mask off." Then, Luke says "But you'll die." My questions, how does Luke know that? And why does he accept that fact so readily?
Vader: "Help me take... this mask off."
Luke: "But you'll die."
Vader: "For someone so powerful in the Force, you won't even try to save me?"
Luke: "Uh... lemme get a moist towel then."
Vader: "Should'a tried to get the sister to help me..."
Seriously, the questions above are the focus of this thread.