Complex sentence: Danny Boyle said in his commentary on the 2009 Special Edition DVD and 2012 Blu-ray that Alex is not meant to be dead, so the line of Alex saying hello to the detective was added in post-production to clarify this.
Split into simpler sentences: Danny Boyle said in his commentary on the 2009 Special Edition DVD and 2012 Blu-ray that Alex is not meant to be dead. Boyle stresses that a line of Alex saying hello to the detective was actually added in post-production to clarify this.