MC might not know it yet, but his sister is much more cunning than they give her credit for. She aint gonna be an obedient puppet. Just see previous chapters.
What's this? Actions have consequences???!!! hOw cOuLd sUcH a tHiNg bE?!
Joking aside, it's good that the girl realizes the gravity of the situation she caused and did not try to run away from it.