Deep down, Dexter knew it was a futile attempt for him to get away from this current situation. He wouldn't be able to save Aria.
But still, he didn't stop running with her on his back. She was too shocked to move when she finally realized she lost her parents and the people that she knew.
They didn't have time to wait until she could get over her grief. They had to move as far as they could, that was the only slim chance they had.
"Why? Why did you do it?" Aria asked, crying. She shook her head, as if she wanted to get rid of the noise in her head. People were crying and screaming and that sound would be forever etched in her mind. "Why? What have done wrong that you wanted to kill us?"
Dexter couldn't answer her question. He didn't know how to answer that. The only thing that he knew he had to get her away from his people and for the aftermath, he would think about it once they were safe.
