@circlegod,
If it's day game, and even a lot of the time with night game, I communicate that I am busy / in a hurry and only talking to her for a moment.
You can use
false time constraints for that. You can also communicate it through body language (body rocking away from her, etc.).
Another way is framing yourself as not really wanting/intending to be there. If she's in nightlife because she likes nightlife but you're there for some reason other than wanting to be there, and actually you are busy and should be elsewhere, you frame yourself as higher value. If she's walking through her part of town in a leisurely way but you are just there to pick something up and get going, you frame yourself as likely higher value.
If you're overseas, I know there are a lot of guys who like to do the "I'm in your country because I'm fascinated with your culture" bit, which is not bad, but personally I always frame it as "That's a good question. Why am I here? I had a friend who invited me and ended up getting sidetracked. I probably ought to keep moving, huh? It's a nice country though."
Chase