Overseas isn’t a good word for moving from one place, to another place that has a large land border with the first place.

“Would you want to move overseas?”

(looks around furtively) “Absolutely not! I am a patriot!”

“What about either abroad or to mainland China?”

“I could do that, yes”

I find that hard to believe. Probably equally as believable as when a mainland Chinese person says nothing happened in the weeks between 15 April and 4 June, 1989.