The decision that would throw them over the edge of a new tomorrow (or a new yesterday, depending on how you like to keep time in unusually non-linear narratives experienced through active participation) would be an impromptu one only on the surface. That wasn’t to say that it was carefully planned – more that they had pondered it for a long time (or a long period of what would be called time if Hermione hadn’t stretched her magic over their little corner of the ice cream shop for the majority of their conversation).