The Other Side of This Life
Season 3 | Episode 22 | Aired 05/3/07
Susan comes back to the hospital with a fever and a murmur and later has cramps. Meredith thinks it may be a bad reaction to the antibiotics and reassures Thatcher that everything is okay. But then Susan becomes septic and they have to rush her into surgery. Thatcher paces anxiously in the waiting room and Meredith comes out to tell him they did everything they could, but that Susan is dead.
In a move we didn’t see coming, Thatcher slaps Meredith across the face. "She had the hiccups!" he says over and over. "I trusted you." Derek tries to grab Meredith before she runs off, but he can’t stop her. Derek goes by Meredith's house later. He sees her knocking back tequila shots with Izzie and Alex. We can only assume that Derek feels like he doesn’t belong there, and that’s why he just walks away.