Well, Satori's used to read minds, so I guess the fact that she can't read her sister's mind (of all the people) would make her a little frustrated/confused/doubtful (about Koishi). I mean, Satori would like to know where Koishi was, what made her do what she did and why she left her for that long.
That last panel is cute, but I seriously, the first impression I got upon viewing that, was some serious metal gear solid neck snapping action was imminent.
HuffHaaffHfffAround here...I know it was around here!Where!!?ThmpfOh, that's right.Yes.I realized it the moment I got there.I hadn't sensed any other thoughts......than Okuu's.So of course she wouldn't be—Eh?Aren't you glad, Satori-sama?FlapPffOh!Back then...It's very cute!Hee hee hee!Let's go pick some together next time!And you know what else, sis? You know what else?Out back?What is it, sis?You know this flower you gave me?You know what? It was growing in the forest out back.You know, near Furnace #6?I'm in! I'm in! I'm in! I'm in!...we had words......for just the two of us.Koishi!Koishi!Koishi? You awake?HfffKoi-FlapClenchKoishi!Please, Okuu!Don't lose sight!Of Koishi!PuffPantAh! It's Satori-sama!Okuu!!!-shi...