Why did the police say they owed one at the end of the Great Britain War?

In the ending of the movie "Great Britain War", one of the main reasons why Guan was not shot by a sniper was that Guan helped the government eliminate many terrorists. The last sentence of the policeman: "I think we owe this man a favor." This also shows that the police think they still owe a favor.

However, in the end, hannis was surprised to learn that her lover was actually one of the undercover officers of UDI, and the government, Guan and others suspected that hannis was involved in the terrorist attack. So Guan found hannis and asked hannis to publish intimate photos of him and his lover, so that hannis was completely finished.

The ending of this film is an open ending. What will happen to Guan and hannis next? Will Guan be shot? The film did not give an answer, which also left a lot of room for interpretation for the audience. Of course, it is also possible to make a second film.