On Wall Street, Vivian Tu could entertain clients until 4 a.m., shower, and return directly to work. But her mentor told her never to admit it. The rule was no

On Wall Street, Vivian Tu could entertain clients until 4 a.m., shower, and return directly to work. But her mentor told her never to admit it. The rule was not really about staying out late. It was about knowing that the same detail considered harmless for one employee could become ammunition agai…