Or was it the eldest one that did it, that's very cruel to do, just because he was playing with one of their toy aeroplanes, if the father had've been home she would have received a much more severe punishment, also to me the son is definitely the favourite child of the family and the two sisters are trying to get their parents attention.
shareI think the older sister is the one who attacked the brother, and i guess her aggressive response is maybe due to the awakening of her sexuality after performing on Christina a couple of scenes earlier.
These things strike me as very much the least of their problems.
"What are you lookin' at? You're butt-ugly, I didn't say anything!"
They are living in isolation and outside of what they are told by their parents they have no idea how to conduct themselves in an acceptable, normal manner. She is simply getting revenge and doesn't understand the concept of violently cutting her brother to be wrong.
If you watch the film carefully you'll actually notice that they have many scars amongst them.