Author's Note: So this is my speculation on what would have happened if Jason Grace shut the Doors of Death.
The sound of Battle rang in the air. How did it come to this? Jason wondered. I'm not praetor anymore... Frank is. It's not my job to lead them anymore.
Frank was leading the dead Roman legionnaires into the fray. Percy and Annabeth were as safe as they could be. Jason thought back to Achelous. Piper really should have listened to him. I hope she finds someone else. Jason knew that he had been raised to lead. That was why Hera had taken him from his mother, or rather his mother had sacrificed him. His head hurt with the knowledge of what he had to do, but his heart told him that he had finished his journey. He would go to Elysium. A double lock. The Doors of Death had to be shut from both sides. And it that moment something in Jason snapped. He knew what he had do. He had to shut the Doors of Death. The Roman Ghosts had desecrated most of the monsters. His friends were looking at each other. Piper was looking at him. It was only then that he realized he was standing right next to the Doors. How did I get here? He must have subconsciously walked here. He could feel the sand of destroyed monsters covering him. Goldish flecks of dust fell to the ground as he pushed his blond hair out of his face. After what seemed like an eternity but was really only a few seconds Piper spoke.
"Jason," her voice quivered, "What are you doing?"
His hand strayed to the Doors that were still open.
"Piper," his voice cracked,"I hope you find someone... but this is my responsibility."
A chorus of protests came from the others.
"You can't!" Piper protested her voice shaking with sobs,"You can't leave me here!"
Jason turned back to the Doors. He walked to the other side. The other seemed paralyzed. One hand on either of the Door he looked at them,"I'm sorry," he stated mournfully,"but I have to do this. Take care of yourselves." The Doors slammed shut.
Jason wasn't on the other side 30 seconds before a vengeful monster stabbed him in the heart. He didn't resist when he felt the darkness consume him.
Author's Note: Yeah, did I forget to mention this story is all angst?