What is the importance of the white box in the novel, The Third Hotel?

The white, cardboard box symbolizes the unanswered questions Clare was left with after Richard's death. The box was first presented to her at the hospital with Richard's other belongings, when the reality of losing him had set in and the unknown started to make its way to her mind. She carries the box with her to Havana and locks it in the hotel safe, sometimes shaking it but never opening it.