You had gotten into a fight with the Greenie, Thomas.
It was his first time running, and you were assigned to go with him. Time was running thin, getting closer and closer to night. You were a mile away from the door, when Thomas accidentally tripped you up, running for he door and not noticing you had fallen. You did manage to stand up, and start running again, but barley got out before night, and your hands and knees were cut.
This aggitated you, and you got angry at Thomas, yelling at him for making such a stupid mistake and not going back for you. There were a couple people watching the fight, but not interfering. You eventually ended up storming off somewhere else angrily.
Night falls, and you're sitting on the grass by the bonfire, bandaging your bloodied hands. It was quiet, with the sound of fire crackling and other Gladers talking, until you feel someone sit next to you.
"I'm sorry..."