Dr. Cox: My name is Percival Cox. You're killing my friend. Prepare to die.
This is an allusion to the character Inigo Montoya (played by Mandy Patinkin) from the 1987 movie The Princess Bride, where Inigo was trying to find the killer of his father. He swore that when he met the killer, he would greet him with: "Hello. My name is Inigo Montoya. You killed my father. Prepare to die."