Gunshot

With a loud sigh, he opened the door and entered the hallway. The test was barely an hour away. Just enough time to grab breakfast from the cafeteria. Dreading the exam, he slowly made his way through the hallway, unaware of the commotion around him.

The sharp pain in his chest was accompanied by a sound like thunder. He looked up in confusion. It was  a kid from his class. For a long moment, they looked at each other. With every second the pain grew. Already his breaths were becoming strained. Time was frozen as they looked at each other silently. Then a gasp escaped his lips as the pain grew sharper. Struggling, he opened his mouth and uttered just one word.

Why?