As Daniel enters the subway station in Harlem, he prays to the subway gods that he'll make it to his destination with no issues. He hopes that the time it took to give a dollar to the violinist didn't make him late. When his train pulls into the Fifty-Second Street subway station, there's a downtown train across the platform. While both trains are stopped, a flash mob dances on the platform. Subway passengers applaud as the dancers scatter, and people smile at each other. Daniel wonders if this was the dancers' intention.
The power of people's smiles here calls Natasha's earlier assertion that life would be easier if emotion didn't exist into question, as the flash mob clearly demonstrates that emotion and the ensuing sense of community are positive, powerful things. His mention of the violinist shows that he believes his actions there will be connected to and influence what happens in the future.