What do cigarettes represent?

Cigarettes symbolize deception, which becomes combustible in relationships. Mary and Matt surreptitiously smoke by the creek, and share intimacies that should probably be shared with others, such as Matt's wife, and Mary's mother. Additionally, Pak lies about his cigarettes, which impedes his relationship with Young. The cigarette used to ignite the fire that results in the fatal explosion is Pak's attempt to deceive others into thinking the protesters are to blame.