Not to mention her eagerness not to have someone falsely blamed. Given the Joker wasn't a suspect, you'd think . . .

[But Rosalind firmly believes everyone is selfish in the end. If someone else had been blamed, would she truly have stepped in?]

. . . I suppose it doesn't matter now. For better or worse, she chose what she did. And at the very least, she got what she wanted: no one else died in place of her.