why does hannah come to expect something out of the ordinary will soon happen?

Gitl informs Hannah that there is a plan. She does not go into detail, nor does she tell Hannah what the plan is or when it will take place. Hannah only knows that she will be involved somehow. Gitl refuses to tell Hannah out of concern that Hannah may inadvertently discuss it and be overheard. Hannah asks Gitl again and again over the next days, but Gitl tells her nothing.