I have no idea about why this spot is called "Chemical Suzy's" by Hong Kong street artists, but it is. It certainly looks a lot cleaner and less filled with construction materials than when I last visited (photos, along with a load of other Hong Kong street art here). Any how, I like that a location which is an almost secret gallery of Hong Kong graffiti was included in the film, as it is something which I think is very important to Hong Kong. As some graf on one of the buildings where I work used to read; "blank walls, blank minds".
This is the spot where Wong Cho-Nam hands over money to Jess Sum. The alley way is not on Street View, but you can see the tail end of the graffiti, before it disappears to the stretch where this was shot.