What happened in the elevator area?

According to the story of burning winter, a joke was told. When fireworks were set off, Nana, the protagonist, found that the fireworks had no primer and wanted to pass it on to the people who set off the fireworks. The fireworks man heard the laughter in the elevator and mistakenly thought he was going to shoot himself, so he shot Nana in the elevator. At this moment, the people in the elevator, including Nana, showed frightened expressions, but then the people in the elevator burst into laughter, pretending to be calm and trying to hide it. Burning Winter is a drama film directed by William Chan and starring Zhou Dongyu and Hequ.