<P> It was also reported as veteran actor Michael O'Neill would reprise his role as the grief - stricken widower Gary Clark . O'Neill later in an interview said, "That role changed my career . It was probably the hardest job I've ever done, hardest work I've ever done . I had a tremendous resistance to it, and I almost turned the role down . I was so afraid of that being sensationalized, and I didn't want that in the world . I hadn't worked with Shonda Rhimes, and so I didn't know . I certainly knew she was a brilliant writer, but I didn't know what the intent was . We had a conversation about it . I said,' You know what? Can I think about this and call you back tomorrow?' I called her back, and I said,' Shonda, I just have to say it frightens me . It really frightens me .' She said,' Michael, it frightens me too .' I thought, OK, we're at least starting at the same place . Her writing was so good...We saw the wound . We got to see the wound that drove him mad, and I think that was terribly important . It was important to show the fracture that brought this man to that desperate action ." </P> <P> Death And All His Friends was originally broadcast on the American Broadcasting Company (ABC) in the United States on May 20, 2010 . The episode was the second half of the two - hour season six finale, the other half being Sanctuary It had an audience in The United States of 16.13 million viewers (5.9 / 17 Nielsen rating in its 9: 00 Eastern time - slot . </P> <P> The episode opened up to universal acclaim with the television critics lauding the writing and performance of the entire cast as well . The performances of guest stars Mandy Moore and Michael O'Neill along with Ellen Pompeo, Sandra Oh, Chandra Wilson, Kevin McKidd, James Pickens, Jr. and Sarah Drew garnered most praise . Marsi from TVFanatic highly praised the episode and gave it five stars, and expressed that it may have been the best episode of the series, adding, "The writing and acting were absolutely stellar, and may lead to many Emmy nominations, but even more impressively, despite a killing spree, it remained distinctly Grey's . Some of the back - and - forths between the characters were truly memorable, and some of the developments so heartbreaking that we don't even know where to begin now . Seriously, the Season 6 finale left us laying awake afterward thinking about everything, a feeling we haven't had from Grey's in years and rarely achieved by any program ." </P> <P> John Kubicek of BuddyTV also noted that the finale was the best episode, adding, "(It was) two of the best hours of television all year . It was certainly the best Grey's Anatomy has ever been, which is saying a lot since I'd written the show off for the past few years . No show does a big traumatic event like Grey's, and the shooter gave the show license for heightened drama with five major characters being shot over the two hours . It was emotional, expertly paced and had me in tears for most of the finale ." PopSugar called it "most intense episodes of Grey's I have ever seen" adding, "What a whopper of an episode! Can we talk about how gripping the scene is where Bailey and Percy are hiding from Mr. Clark . Then he turns around and gets Karev right in the chest . Seriously, I haven't been so shocked by a one - two shooting spree since Michael shot Ana Lucia and Libby in rapid succession on Lost . Another review from BuddyTV called the finale "Game changing!" stating, "The finale that changes everything! You don't want to miss it! To her credit GA creator and writer - of - this - episode Shonda Rhimes pretty much delivered on her promise . I found myself with my heart in my mouth for the entire evening before finally being able to exhale as the credits rolled ." The review lauded Ellen Pompeo and Sandra Oh adding, "The Twisted Sisters really were the showcase of the entire finale . Meredith, side - lined for much of the season, took center stage" even calling Oh's Cristina Yang a "rockstar". </P>

In which episode of grey's anatomy does derek die