I'm still of the mind that "big guy" is going to provide the crisis between the two that will either cement their love or drive them apart. Maybe its my long immersion in corporate nonsense but he's definitely riding on Masumaru's rising star and the steady move into Aka's "personal space" is pretty obvious - though she hasn't said anything yet. I suppose its too much to hope for a nice simple "Lamune" convergence
Been a great series so far and I'm pretty sad its so short - though it is a clever exercise in story telling.