Well, now that I know the location of the zig-zag staircase, it's fairly easy to see that this shot was taken at the top of the staircase along Blue Pool Road. It shows Jared Martin, Robert Ito and a very young Victor Kan trying to track down the artist who just so happened to draw a picture (very quickly but also very detailed) of the scene when Martin's sister is kidnapped by the evil Joseph Wiseman and his henchmen. All very far-fetched indeed.
I can't get an exact match on the angle, but the film was shot at the top of the staircase between Mafoo Quarters and the neighbouring UNICEF building. The staircase is now fenced off in between the two buildings as you can see.
I have no idea if 60 Blue Pool Rd is the same (but modified/extended) building seen on film. It's style at the front suggests it probably is but it would be nice to have confirmation if anyone has any idea.