"Petra." Levi it back the bile in his throat. "How could I have let this happen?" His eyes closed in silent despair. He clenched his fists. "I need to find Eren." He shot off toward the last remaining member off his team. Levi found Mikasa a few yards behind the female titan looking like she was about to do something that would get herself killed. He pushed the images of his dead comrades out of his mind and focused on the mission.
Feeding his dead friends to the titans was the hardest thing he'd ever had to do, but it wasn't them anymore. They were just empty corpses. It was the only way to save the friends he still had left. He ignored the disgusted looks from the regiment and kept his eyes forward, focusing on the overwhelming hatred he felt for himself. He let it consume him, he deserved to be engulfed in guilt and pain.
Levi clutched Petra's regiment crest patch in his fist and hid his sorrowful face from the other scouts. The ride back to the city was the longest of his life. Levi didn't think he could face Petra's family. He briefly considered asking someone else to inform them, but quickly dismissed the idea. It was his duty. As her scout leader, and as her... friend. He would need to get himself together first. He took a deep breath and began the process of clearing his mind.
When they reached the inner wall, Levi nearly turned tail and ran, almost preferring titan company than the shame of confronting the citizens who lost loved ones. As they entered the city, the first face Levi saw was that of Petra's father. He couldn't do it. Looking at his smiling face, Lei shut down. He didn't speak, he didn't get off his horse, he didn't even blink.
Petra's father came up to his horse and walked alongside them. And as he discussed his deceased daughter's impossible future, for the first time in a long while, Levi wanted to cry. He finally broke when the misfortunate man mentioned marriage. He gasped and clutched at his chest, sliding off his horse. He'd never felt so much pain before.
Petra's father cried out for help, trying to hold Levi off the ground. With a ferocious sense of determination, Levi shoved Petra's crest into her father's hand and whispered to him, "I'm sorry."