Death is a funny thing. The general rule of thumb—at least in sci-fi—is that dead doesn’t necessarily mean dead, certainly not when characters from Spock to Linderman return with frightening regularity. But now dead doesn’t even mean dead on ER. That’s right, ER. NBC’s veteran medical drama will call it a day at the end of its current season, year 15, and they’re pulling out all the stops. Noah Wyle will return for a quartet of episodes, rumors persist that George Clooney will drop by for a visit, and in this week’s episode, “Heal Thyself,” Anthony Edwards will reprise his role as Dr. Mark Greene, who succumbed to cancer – remember the tears, the “Be generous… with your time, with your love, with your life” conversation between Dr. Greene and his daughter, the Hawaiian beach, “Somewhere Over the Rainbow,” etc.?—at the end of season eight.