Editor Hank Corwin has cut for Oliver Stone, Robert Redford and Terence Malick. Now he’s getting acclaim for “The Big Short,” Adam McKay’s dramedy about a handful of investors who saw the corruption in the American housing market before the great 2008 crash and bet against the banks, even when everyone thought they were crazy. In a video portrait as unique as the film, Corwin reveals how he thinks about a script, about characters, and his own ­­ often unusual ­­ way of working. (You’ll want to watch this one all the way to the end.)