Color appeared in snippets of the film to this point -- most memorably a leitmotif shot of the Iguazu Falls, Lai's reason for wanting to visit Argentina and a metaphor for the film's conflicts that becomes decreasingly obvious as the narrative progresses -- but Wong switches entirely to color as Lai drives Ho home from the hospital. His badly injured hands entirely bandaged, Ho cannot fend for himself, so Lai takes him in to help his ex recuperate.
The reversion to full color clearly reflects Lai's excitement, despite his better judgment, at the prospect of nursing Ho back to health and possibly reigniting their relationship, the monochrome of his depression replaced by the vivid spectrum of hope. What it instead captures is the vibrant effrontery and the complexity of Ho's manipulation of Lai's crippling codependency. Wong's precise casting allows the audience to better understand the divide between these two characters. Cheung, who of course appeared in Wong's Days of Being Wild, where he also toyed with his image as a founding member of Cantopop, plays Ho like a rock star without the stardom, a balls-out loon with thirsts incapable of being slaked. Leung, on the other hand, is one of the most subdued and affecting of any actor of any nationality (or generation, for that mater). His strength lies not in the explosive movements that Cheung brilliantly unleashes but in the internalization of his feelings and thoughts until they bubble into his eyes, where they become unmistakable and devastating. To see Lai hurt is to see Leung hurt, which only compounds the effect of the poor man's tribulations on the audience. Lai attempts to shield himself, resisting Ho's physical and emotional teases, but his desires get the best of himself and he reenters into a romance with Ho, restarting the cycle.