[Just the person he was thinking of! He offers a bit of a smile.]

Everything's okay. I've just been thinking about a few things that have happened.

[He doesn't need to specify whether they happened here or at home, not unless he's asked. But he thinks Adachi probably already has some ideas of his own.]

Of course, it's more complicated than just "if I could have done this differently, then that would have turned out differently." Sometimes, things will turn out a certain way no matter what you do.