The fact that Tris had still been walking and talking at all by the time she reached David was impossible, but there it was. She could feel that heaviness, like death tugging at her, but somehow, she fought it off even as she talked to David. Stalling, she was stalling. She was trying to distract him as she backed toward the box that would release the memory serum. Finally, she was close enough and she turned.
David's fun went off. Once, twice, how many times? Tris' body was both numb and filled with so much pain she could barely breathe. There were dark sparkles dancing in her vision and she felt herself start to fall. It was only by chance that she managed to hit the right button on her way down to the floor. As she landed, Tris became vaguely aware of a dampness on her neck. It's dark, warm, sticky. Blood, she thought vaguely.
When she saw her mother appear from behind David, Tris knew she had to be imagining things. "Am I done, yet?" she asked anyway. Even then, she was worrying about her friends, about Tobias and Caleb, but Tris was tired and as her mother nodded and assured her they would be fine, she finally let herself close her eyes. Maybe she would just rest for a minute.
When Tris opened her eyes again, her surroundings had changed. There was a girl just a little older than her bending over her and as Tris looked around, she could see headstones, grass, dirt. A graveyard. I'm in a graveyard. "What- how did I get here?" she asked once she found her voice.