LOL - any city at 2am is somewhere to keep your eyes peeled and your back covered
But Hong Kong is the one I personally feel safer in 24x7 than anywhere else. No contest: NY, SF, LA, Sydney, Seoul, London, Paris, etc ... Actually on reflection I even feel safer here than in Tokyo ... even at 2am ...
Personal safety is fine - navigation might be a challenge of course, but then he's got time ...
My comments were addressing the tone of his question "what's my best bet?" ... yes if he can find a HG or walkup at that time, it would be a tad easier and safer, but it's by no means a sure shot by that time. If he's prepared with a map, reads up on the reports in this forum, and carries them with him it's by no means a tall order even for a newcomer. But yes, a newcomer who's already a seasoned traveller.
Sissy!!