For starters, Maggie (Kelly McCreary), after spending the first half of the episode struggling to wrap her head around the fact that her mom was getting a "boob job," discovered that the real reason her mother was undergoing cosmetic breast surgery was because she has cancer and requires a mastectomy.
Tensions between Amelia (Caterina Scorsone) and Owen (Kevin McKidd) also came to a head, culminating in Amelia (unfairly?) screaming at Owen in the middle of the hallway that she feels suffocated by him -- and she bets Cristina felt the same way and that's why she left.
Riggs (Martin Henderson), meanwhile, is pestering Meredith (Ellen Pompeo) to give him an answer about whether he stands a chance with her (despite explicitly telling her previously to "take her time"), and Meredith finally blurts out that she doesn't see even a single reason to go out with him.
Wooed, she agrees to go to dinner with him.
Unfortunately, Amelia discovers that the wife, Elsie, has a brain bleed (you know where this is going) and after undergoing a risky surgery because she desperately wants more time with her husband, she dies and her poor, disoriented widower is left on his own to figure out how to fend for himself.