I remember discussing this same question before---why didn't he get rid of her that night, so late and remote?
I think he wanted to, and may have considered it. But she may have saved herself that night, by mentioning her family, and how she would be talking to them, on Thanksgiving.
He probably realised that she would have been missed quickly, if no one could reach her on that family holiday.
They'd know she wasn't at work, should be at home, and she would call them to say Happy Turkey Day, at some point. And if she didn't, they would know something was wrong.
So she postponed her execution by a day or so...