The choice
Facing Sierra's wrath Percy finally realised his wrongdoings. He felt ashamed of himself that he had attacked his own brother with a forbidden attack and jeopardized his future as a fighter.
In his true heart he never wanted any harm to befall on his brother however he did not want him to surpass him either. Muddlehead in the face of the intense fight he made an irrational decision and was extremely regretful for it.
Since the rewards ceremony was starting Percy was supposed to be present at the grand arena , hence dragging his sore and broken body to the fighting stage , Percy prepared an apology in his mind.
As he was walking out he saw grandmother Luna talking to some officials in the tunnel , however although she glanced at him there was no warmth in her gaze. She only gave him a long and fierce look that said ' This is not over, boy '
Percy felt even more regretful about his choice of attack , it seemed like he had antagonized the entire family.