She sensed that they expected her to fall apart, but she didn't know how to fall apart. She knew it was strange. She looked the same despite this massive piece of herself that had gone missing. She acted the same. She went to work, greeted people, went home. Everything normal on the outside, except the occassional muffled crying on the job.
It might not seem self-evident that impunity for white violence against blacks would engender black-on-black murder. But when people are stripped of legal protection and placed in desperate straits, they are more, not less, likely to turn on each other. Lawless settings are terrifying; if people can do whatever they want to each other, there are always enough bullies to make it ugly. Americans are nostalgic for the village setting and hold dear the notion of community, so the idea that the oppressed do not band together in solidarity is counter to our myths. But community spawns communal justice; the village gives rise to the feud.