Below are five sneak previews of this week's episode of Grey's Anatomy, "Give Peace a Chance." As advertised, it's all about Derek this week, and McDreamy goes rogue.

When Derek learns that an employee is walking around with a spinal tumor that should have killed him, he is determined to operate on Isaac despite very difficult odds.

Here's the two of them discussing the tumor in question ...

[video url="http://www.tvfanatic.com/videos/give-peace-a-chance-sneak-preview-1/" title="Give Peace A Chance Sneak Preview #1"] [/video]

Poor Isaac. Good thing Derek is so dedicated, even if the Chief stands in his way. Follow the jump for four more clips from the episode, all about this particular story line:

[video url="http://www.tvfanatic.com/videos/give-peace-a-chance-sneak-preview-2/" title="Give Peace A Chance Sneak Preview #2"] [/video]

[video url="http://www.tvfanatic.com/videos/give-peace-a-chance-sneak-preview-3/" title="Give Peace A Chance Sneak Preview #3"] [/video]

[video url="http://www.tvfanatic.com/videos/give-peace-a-chance-sneak-preview-4/" title="Give Peace A Chance Sneak Preview #4"] [/video]

[video url="http://www.tvfanatic.com/videos/give-peace-a-chance-sneak-preview-5/" title="Give Peace A Chance Sneak Preview #5"] [/video]

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.