They don't go out for lunch. Anna drives them straight home because it's what Elsa wants and needs.
She needs time, more than anything; time, and a chance to grieve. All Anna can do is be there for her.
She sits numb in the passenger seat, and doesn't say a word.
Doesn't break down until she gets home and realises... that it was supposed to be a home for four.
Elsa goes to the nursery. She sits on the floor, arms wrapped around her middle, and sobs.
Anna sits next to her, and holds her tight.