From the 2005 pilot, through its current 16th season, Shonda Rhimes' ABC medical soap Grey's Anatomy has entertained, infuriated, and caused all kinds of audience swooning with its sexy doctors getting into all kinds of sexy doctor shenanigans. Alongside the ride since the very beginning is Justin Chambers, who's played fan favorite Dr. Alex Karev, introduced in the pilot as a surgical intern before rising the ranks to resident and then pediatric surgical fellow (while dating and marrying, like, everyone on staff at Seattle Grace Hospital). But now, according to Deadline, Chambers is leaving the show, saying goodbye …