She laughs again, that same little half-bewildered inescapable sound as before. "If I'd known it was you I'd have brought the whole cow," she jokes back, and still it's all surreal. Then she shifts her eyes back to her brother's profile, her brows knit. "Of course I looked for you. I tried calling, too... before the lines went down." She thinks of his letters, but she can't even bring herself to mention them - not yet. They still stab at her heart, the progression of emotions, the paths he went down while they've been separated. She thinks of her own paths since they have been apart - Thomas, Charlie, things she isn't precisely proud of... and it's then that things start finally clicking in her brain, things she didn't have any reason to think of before but which now are completely, utterly vital.
She came to meet the Dog King today because she has suspicions of Thomas, of his need for control over her and the things he would and has done to get a little insurance. She knows, fully well, that she can't just walk away from Thomas despite that fact that she would - she would take Charlie and walk away from Thomas in an instant if she knew she could to go wherever these two are. She knows it's what they will expect, too.
But Thomas would never let her walk away. He would come after her, after the son he is so proud of, with everything the Capitol has.
And if Rodeo knew that she wanted to walk away and Thomas was stopping her? There isn't the slightest doubt in her mind that that would be even worse. She knows how Rodeo thinks, she knows his temper and his reactions, and she knows that he would take whatever guys he has right here and now and storm the Capitol and get himself killed.
Neither of those things can happen, and Adelaide realizes that she is about to walk a tightrope to keep it all from imploding.
All of this runs through her head in a matter of instants, connecting dots and predicting outcomes, and all the while her expression doesn't change. "I never stopped trying to find you, until I thought I did," she says.