Scott Beigel was reported to have been shot as he shut the door to protect students from the gunman, an expelled student identified as Nikolas Cruz. One of the students in his class, Kelsey Friend, recounted how Beigel, 35, let her and other students into his classroom and then attempted to lock the door. They volunteered. They played soccer. They went to camp. They were sweet, mature and easygoing. They were just beginning their lives, or helping others on their way.