Jeffrey Dean Morgan (Denny Duquette) although appearing throughout the entire episode, only says the last five words "Are you sure you're okay?"
The actor who portrays Michael Norris (Tom Verica) has also directed multiple episodes of Grey's Anatomy from seasons 3-8.
George Coe plays two different characters in Grey's Anatomy and Private Practice (2007) (a spin-off of Grey's Anatomy). In one episode of Grey's Anatomy he appears as Ed, a man whose wife is dying, and in Private Practice as Stan, a man whose wife is concerned about his sleeping issues.