Roy Mustang had a sinking feeling that the whole situation was a little too good to be true. Much like most situation of his life; and he knew from past experiences, that if something was too good to be true then it was. However, of all the possibilities he never thought that situation would be attached to seeing Fullmetal again. Of course, seeing Fullmetal again was what he wanted but, somehow he almost knew it wouldn't be lasting long; he could feel it in his gut.
Fullmetal had brought trouble, which was surprise. The boy after all had been one of the biggest trouble magnets he had ever know during his life. Noone could attract as much trouble as the small blond alchemist could.
However, working with Fullmetal like always, was an adventure. Not that he hadn't ever worked with Fullmetal before because he had on a few occasions. Each memory seemed to be embedded in his mind. Mostly because there had been lives at stake.
Mustang was under no delusional that Edward was planning on staying in Amertis with him; to think that was nothing but foolhardy. However, it did make out for a nice fantasy but that was all it could ever be. Roy knew for a fact that Edward would probably only stay for Al; Al was Edward's life in a way. Not that Roy could expect any less, after all Edward had spent years of devoted his life to making Al human again.
So when Fullmetal had been standing on the other side of the platform and Al and himself on the other platform; he couldn't say he was surprised very much but in a way he was. Perhaps, some part of him had been hoping that he could make Fullmetal stay, it was anyone good guess but maybe he thought that he, himself could make the blond alchemist stay in this world. That for some reason, thought that he would be enough to make the blond alchemist stay.
Alas it didn't seem to be because it seemed that not even Al could convince the Fullmetal alchemist to stay. If Al couldn't do it, what made Roy think he even stood a chance?
The blond alchemist left with no heartfelt goodbyes or anything close to it. Could Roy really expect anything less? If Roy even thought Edward said anything close to heartfelt, it was simply all in his mind.