The only thing racial was that the employee assumed the two Chinese guys knew each other. She pre-judged that fact based on their race. As for thinking they were terrorists that probably had more to do with her psychological state...

> "How much are they paying you?" he said she asked him, not clarifying who "they" were. "Did they give you a visa? Did they give your family a visa? Do you make a lot of money? Do you work on Wall Street? Are you on an American visa?"

She probably wasn't asking him that because of his Canadian citizenship.

Perhaps she thought they were some sort of Chinese government terrorists. Seems like a plausible enough jump for a mentally unwell person to make given the rest of the things she said to them. Can’t know her motivations either way though.