I feel sorry for Hannah.
I read an interview that said they did research with children who have been taken away from their parents or had their parents taken away, and they spoke to psychologists and they said a lot of the children can't understand why their parents didn't "try harder" to stay with them or find them, which is what Hannah said to June.
They said they will remember and relive the last time they saw their parents, so Hannah will have been thinking of June getting hit on the head as she was taken from her, and Hannah did remember and asked her if it hurt.
They are also comparing it to what's happening in America right now and said when they were doing the research they never thought it would be happening for real in America as the show was airing.
And they talked about Emily being told she couldn't go to Canada because of the law, and her saying what law and being told "THE LAW" as her answer. Apparently Jeff Sessions has said that over the removal of children at the borders, and used the bible to back it up.
It's horrific to me to think of those real children, real families, having this done to them even as we speak. Apparently that's something like 2,300 children so far and nobody knows if they will be reunited with their families. The writers said they wanted to show the long term impact on children like Hannah and how even from such a young age it's never okay for them afterwards. They don't forget, they are affected for life.
Be careful of googling though in case of other spoilers in the interviews. Some of them talk about the three episodes we still haven't seen.