In a recent bloopers video, Yen was captured telling fellow actor Benjamin Lam to punch him harder during a fight scene in a sewer to achieve a better shot. Yen said he felt dizzy afterward.

The film's links to a classic crime story also contributed to moody cinematography from Edmond Fung, who said complex and dangerous scenes featuring car chases, gunfights and explosions were designed to have maximum impact. These scenes called for concentration, dedication and precise teamwork.

Fung said that early one morning, the actors and crew of Raging Fire were pressed for time, as they needed to complete a scene in which a police squad rested and chatted after a wild night of pursuit.

He and Benny Chan used a police vehicle prop, with monitors on the dashboard, and steadily drove through actors and actresses on the set, as performers read their lines.

"This way, we got the best sequence as quickly as we could," said the renowned cameraman behind New Dragon Gate Inn (1992) and Operation Red Sea (2018)－the seventh highest-grossing film in China with 3.65 billion yuan.

Kinson Loo, CEO of Z CAM in Shenzhen, Guangdong province, whose cameras are widely used in action scenes, said anyone who visited a movie crew on set would be impressed by Hong Kong filmmakers' flexibility and working spirit. Loo has worked with film producers around the world.

Loo said crews react to unexpected situations extremely quickly and take the minimum amount of time to reshuffle a schedule, reprioritize and relocate.

Director Wong Jing said Hong Kong filmmakers always make every effort to do their best. Martial arts have been "borrowed" by many filmmakers overseas, mostly for digital effects. "Audiences still find it different seeing our actors in real action," he said.

"I never believed that Hong Kong cinema had died. It's been here all the time, being welcomed by some. We make small breakthroughs one film at a time."