Question about the climax to Wait Until Dark (1968).


WARNING: "SPOILER" spoilers below
Why didn't Susy just give them the doll once she found it? She's blind so it's not like they are going to bother to kill her, since she cannot ID their faces, so why not just give it up, rather than die? Did I miss something? And why did she drop the knife, just beceause the guy who broke into her house told her too? Wouldn't she at least want to try to defend herself?

"Money won is twice as sweet as money earned."