Well, if she ever wanted to become an adventurer like she was thinking about in the main comic, this would definitely prove that she has fighting spirit/rage.
But dang, I'm wondering if it's a combination of both rage and survival/protecting her now terrified sister. I know we've all been saying that it's about survival; however, is it really that big of an issue in this society/culture? What would happen if their brother didn't fight for them? Anything?