Nicole used to be one the the girls in the ritual now sent to recruit/initiate Tom's character. Look how she takes of her robe at the beginning of the movie...same as the girls in the circle in the ritual. She gave her daughter up to the same fate /life she lived . Taken young abused and brainwashed creating basically a human robot .
Notice every other child in the frame is being touch or held by their parents as to not get lost in the huge, crowded store. Neither Alice nor Bill's body language seem like they want to be there. And theyre only paying attention to their daughter when she calls out to them. Then they both give her a gentle touch on the shoulder as to say goodbye, she follows the two older men away and Bill and Alice never bother to look for their daughter again. Their conversation is self centered. No worry of their child because they know where she has gone.
Alice saw the two men, Bill didn’t. You can tell in her demeanor she knew what was happening. She gave them her daughter so her and bill wouldn’t be killed. She’s in the Cult - Bill can’t see that. That’s why it’s called “Eyes wide shut.” He can’t see his own wife is involved.