ScreeningNotes’s review published on Letterboxd:
"When did everything start having an expiration date?"
Missed connections; uncountable separate individuals swarming around together in the same shared space. The first lines of the film, spoken by He Qiwu, are "Every day we brush past so many other people, people we may never meet or people who may become close friends," expressing a sort of wonder at the sheer number of people who are living together in the same place yet who will likely never become close—people living together, but separately.
In the second major section of the film, Faye goes to Cop 663's apartment while he's not there and performs a wide variety of activities, from cleaning and organizing to adding fish to his aquarium. In this way, the apartment acts as a microcosm of Hong Kong (and, to extend the metaphor, of the world): Faye and Cop 663 occupy the same space independently, they live together separately, the same way that the "so many other people" of Hong Kong live together separately, the same way we all live together separately.