From left to right:

*Fei and Quin are eating cheesecake at Hong Kong Park. There's one piece (of cheesecake) left. Fei was about to eat it. Quin, who already ate alot, wants more. Fei teases her about gaining weight. But, Quin manages to convince Fei to let her have a couple more bites...

*Quin prepares dinner (at Fei's apartment, of course). She comes out of the kitchen hearing "Big Big World". She soon realizes that it's the radio playing this song, not Fei playing the CD.
Note: this scene came right before the scene where Fei was driving Quin home and came across the location of one of the murders.

*Fei and Quin are watching a movie at Fei's house (as usual). Quin mentions that TongSum is a more suitable match for ChiSan than AhMan is.
Fei: Sun [new] foon [love] xui [is] ho [good], kul [old] oi [love] nan [hard] mong [to forget].
Quin gives him a stare and Fei realizes that he said something wrong and quickly adds
Fei: Awe [I] gong [say] ha ja, lay [you] mo [don't] dong [think] zhen [real] wor.
Quin: I know you wouldn't dare (think that). To punish you, you can't sleep in the bedroom tonight. [fuut lay gum man 5 jun hai fong fun...]
Fei: ha... (puts his hand around quin's) I wonder who's been sleeping on my bed... [ha...5 zi been gor fun awe cheung chuang lare...]
Quin: I don't know...