Funny, seems like Shimada's reaching something Rei reached long ago: the realization of the potential weakness caused by his happiness. What Rei has, though, is the memory of that very source of "weakness" standing determined on a bench to stare him straight in the eyes and declare that she wants to do everything she can, together with him, to ensure that she never weakens him in any way. I'm hoping it happens now, but I'm sure at some point we'll see him prove that this sort of weakness can very easily become a strength.