Racial discrimination at Duke University's Biostatistics department The director of graduate studies at Duke's Biostatistics department has stepped down after her racially discriminatory emails, targeted at their international Chinese master's students, went viral on the Internet.

How can an affected Chinese student in the program proceed with their semester safely, without facing retaliation?  

They have been threatened with no research opportunities and other possible impediments to their job search, for speaking Chinese loudly in the student lounge and in other areas outside of class time; namely, while I can appreciate the support for the director and distinguishing between her good intentions and unintended discrimination in her email messages to the students, the threats of retaliation by a couple of professors are problematic, e.g. these professors asked the director for photos of the Chinese students and were subsequently targeting them with no research projects.
I believe that for the students the situation has resolved itself. But I expect that it was collective action on the student's part that brought it to the attention of higher powers. I might be wrong in all of this, of course, but I think that people have been made sensitive to the problem and will be less willing to engage in (blatant) discrimination. 

So, it may be that in the short term, things will improve. 

But in general, it is collective action that is needed to bring such things to the fore. Bad things can happen in dark alleys. The light of day is a good disinfectant. But when someone powerful is acting badly, individual action might only make it worse for the individual. There is power in numbers. 

If the students are still threatened, it is good to stick together. 

Individuals can, of course, seek reassurance from their professors. If it isn't forthcoming, more light is needed.