The Spectacular West End

In London's West End, Shia Muslims observe Ashura, a day of mourning for Imam Hussain, the grandson of the Prophet Muhammad. This observance often involves a procession through the West End. The event commemorates Imam Hussain's martyrdom at the Battle of Karbala in 680 AD

They use chains to hurt themselves to demonstrate their empathy for the pain Imam Hussain suffered. This practice is actually common in Iran and other Middle Eastern countries, where people perform self-flagellation with bare backs, causing serious injuries and bleeding. I did not know what it is called and looked up just now; this act is called tatbir (self-flagellation). I don’t want to include their photos here.
In the middle of the scene, a man is holding a small chain to encourage a child to do the same. You can see him in the second photo.
Regarding the DoF, I wanted to create a strong sense of isolation for the old man while still maintaining a clear understanding of the rest of the scene. I wanted the old man to be the central focus of the story.