There are moments when foreign teachers are 'at sea' during their time in China, lost in the unique cultural response to powerful tragic events.

Don't copy other posters they may have missed out a word. It's 'all at sea' and nothing less hahaha!

Unless an FT has boarded a ferry that sails between Hainan and Xiamen, for example. Then he would be in Chinese territorial waters, which are part of China! But he posted 'at sea' rather than at sea!

So, 'all at sea' is correct. You are right.