Grey's Anatomy: 4x07 - Physical Attraction... Chemical Reaction

• Gizzie catches up with the viewing audience when they realise they don't have any sexual chemistry
• Callie asks Bailey to temporarily take over her Chief Resident duties; The Chief finds out and fires Callie, making Bailey the new Chief Resident
  
• Alex discovers Thatcher has become an uber-drunk; Lexie begs him not to tell Meredith
• Lexie wants to hook up with Alex again, McSteamy wants to hook up with Hahn, and Cristina wants to work with Hahn; they all get turned down
• McDreamy and The Chief are "dating"; Meredith and McDreamy are still hooking up
• A new adoptive mother and her baby fall down the stairs; a boy swallows magnets; a woman who gets a face-lift and a guy who can't poop hook up