Stooping to help on a Manhattan sidewalk, an A train dance party and more reader tales of New York City in this week’s Metropolitan Diary.

When a gunman killed two of her students, Ivy Schamis was the only adult in the room. Her journey through guilt and healing sheds light on the impossible role of American teachers.

Gabriel Vilardi scored twice as the Winnipeg Jets defeated the host St. Louis Blues 4-3 in a shootout Saturday night to ...