Alex was not going to start drinking. There were children here, and she was going to be a mature, responsible adult. Therefore, she was going to set an example, and, more than that, she was going to be a reassuring presence to the children who were facing these same horrors that she was. (Worse, because they knew the girl better than she, and some of them weren't yet as jaded as Alex herself was, either.) And that meant no drinking.

She may have been reminding herself of this a lot.