AMC’s breakout hit The Walking Dead ended its 6-episode first-season run with another series high. More than 6 million viewers tuned in last night for the closer, eclipsing the previous series high of 5.6 million posted the previous Sunday. In 18-49, the finale averaged 4 million, also a new record and the highest ever for a basic cable drama series. With a series average of 3.5 million adults 18-49, The Walking Dead also has become the most watched drama series in basic cable history in the demo. The series, based on Robert Kirkman’s comics, has already been renewed for a second season.