This week: Much to her surprise, Skye is named interim chief of the ER, Pratt ponders where his career is headed at County, Luka confronts Abby about what's been wrong with her lately, Gates helps a kid trying to be tough for his dad, Neela rocks her first solo surgery, Morris wants to pump Sam up, and a man's extremely racist son destroys an immigrant woman's family after a misunderstanding of how a factory accident happened.