Shortly after a failed suicide, the Phantom realizes that due to the contract he signed, he is immortal as long as the villain, Swan, remains alive. So, having put up with being manipulated for long enough, he stabs the record producer in the heart. Swan calmly removes the knife, and remarks "I'm under contract too."
Winslow exposing Swan as a monster on live TV, saving Phoenix, and prompting the audience members to mob and murder Swan in a entertainment-overload frenzy.
You gotta love how Swan, upon seeing the masked freak of nature that Winslow has become, still manages to act calm and collected with no hint of fear in his voice.