Towards the end of the shoot for their directorial debut, Cold War, Sunny Luk Kim-ching and Longman Leung Lok-man had a problem - they had run out of time and money to film a huge passing-out parade for the grand finale of their police drama.
"Our producers told us we were already over budget and it was becoming very hard to accommodate the actors' schedules with ours, so we thought we might have to forgo our original idea," said Leung.
"Then we looked out of the window and said, well, how about we just rewrite that sequence and shoot it downstairs?"
The idea was not as odd as it sounds. Edko Films' offices in Admiralty sit across from the new government headquarters.
And, unbeknown to the filmmakers, Cold War became the first film to feature the Tamar complex as a backdrop.
It is perhaps fitting that Cold War concludes at Hong Kong's political nexus, given that the film - to be premiered on Thursday at the Busan International Film Festival in South Korea - is as much a political thriller as it is a cops-and-criminals adventure.
While the basic premise of the movie lies with attempts to locate a hijacked police van containing five officers, the bigger plot thread is the crisis caused by chaos at the top, with two deputy police commissioners trying to impose their varying notions of law and order on the force.
"We were thinking about how to embellish the story when there was a buzz about the Hong Kong police getting a new numero uno," said Luk.
He was referring to last year's retirement of former police commissioner Tang King-shing and the appointment of Andy Tsang Wai-hung. "We had friends in the police who were telling us how their leaders lacked political savvy and were doing all these things which drew public ire," Luk said.
"They were saying how the top brass were sitting in their offices at headquarters and didn't know how things worked on the front line ... It's difficult for the rank-and-file to do their jobs when the bosses don't understand the risks involved."
This conflict features strongly on screen as Cold War pitches the hawkish Waise Lee (played by Tony Leung Ka-fai), who defies convention and exceeds his own authority to start a city-wide hunt for the missing police vehicle, against Sean Lau (Aaron Kwok Fu-shing) who seeks to end the crisis in his own way, including an internal coup which would strip Lee of his powers.
Rather than being merely inspired by action thrillers, Luk said Cold War was born out of his and Leung's fixation on the political manoeuvres of Barack Obama and Hillary Rodham Clinton during the Democratic primaries for the 2008 US presidential election.
"It was a formidable battle, with both parties pulling out all stops to defeat the other," he said.
"And we thought, we haven't seen such power struggles in Hong Kong cops-and-robbers films before, so maybe we should try to weave this into our story."