["What in the world" actually sums it up quite perfectly. Though, it this case it's more of "in which world are we talking."]

I've... heard things of an alternate version of Amestris. [He's heard this from just about everyone from Amestris - and no one seems to know him. Fantastic.] I suppose that would explain it. [It makes him sound stupid to say it though...]

I am Colonel Frank Archer. I worked with you for... an extended period of time. The... version of you I know was killed in Liore not long ago.