They start talking about all kinds of practical things almost immediately when Janice gets back into the room - if Nel should stay in bed that day, how to go about breakfast, the news, and various other things, so they end up not telling Janice.

Not immediately, anyway.

But in the evening, Mary manages to arrange it so that when all children are out of the house or in bed, her and Nel and Janice end up in the same room, so they can tell her together. Janice doesn't fully buy it at first, but she has to admit that it explains a few things, and eventually reluctantly accepts their story. And promises to not tell anyone, and also says that if anything should happen, they can come to her as an uninvolved person any time.