This would appear to be the "graveyard shift" on the job.  The reasoning behind their late (or early) work hours is obvious.  Go where the money is and make sure no one is around in interfere with the work at hand.  The escape from town is just part of the job description.  In the still of this night you can easily hear some shouts being raised and the dim glow of oil lamps being lit as some people investigate some unusual noises they heard and discover they have been robbed.