Amy saw herself as pretty intuitive and good at reading people, most of the time. While she might not be the best at showing her own emotions, she did care about others, in her own roundabout way. The Doctor was one of those that she cared about and she usually noticed when he was getting all closed off and would well, badger him about it a bit, although sometimes she left things as they were and assumed the best out of him. But while this man wasn't quite her Doctor but still the Doctor all the same, she was sure not much changed between this version of him and the one she knew, aside from the fact this one happened to be half human.
"That's because we're not the only ones arriving here. I showed up a couple of weeks ago or so and River showed up around the same time I did. The you I know, he came along a little after and there were people arriving before I showed up and there's been more, since. Like you and the other Doctor over the communications," she explained, as if to paint a picture as to why the airwaves had a lot of activity. It was thanks to a lot of people getting displaced from where they belonged and now they were just as confused as the people who arrived before them.