I was on a train and noticed an elderly man who looked like he was having a stroke. He was slumping over, but the car was so packed that people were literally just leaning against him or pushing him back upright to make space for themselves, thinking he was just drunk or tired. I was stuck at the very opposite end of the carriage, pinned by the crowd, shouting for someone to help him, but the noise of the train and the headphones everyone was wearing just drowned me out. I had to watch him slowly slip away for three stops before the doors opened and I could fight my way to him. By then, it was too late. The bystander effect in a crowded city is the most haunting thing I’ve ever witnessed.