Input (grade 7): Before leaving, Murtagh reveals that Eragon is his brother, and takes Eragon's sword as well.
Output (grade 5): Eragon loses but Murtagh leaves him because he has "tried", telling him that Galbatorix will make sure Murtagh's oaths are stronger next time. He takes Za 'roc from Eragon, because it was Morzan's sword.