Again...for the people that tend to disregard the obvious, Liz was "dressed nicely", even wanted a lint brush for her clothes, she had indicated that she might not return to her regular lodgings that night, she has a flower on her breast she may have purchase with the 6d she earned cleaning that last afternoon, and mints in her hand. She had also been regularly working "among the Jews", who were the proprietors and attendees at the very club she was at. After a large meeting..which created a large mess I would imagine."
I assume that you are implying that she was on a date that night. She might well have gone out with that expectation but dates don't always show up as they had promised. And remember that this was before cell phones so that there would be no way to let her know that something came up. Also, dates can end suddenly on a bad note leaving her out in the cold figuratively and literally. As for the 6d, that was hardly a great deal of money. I know that you absolutely refuse to believe that she might have resorted to soliciting under those conditions but to me it certainly seems like a reasonable possibility.