Categories of life

The categories of life was a system used to classify people on Earth during the events of Miracle Day, when people stopped dying. Badly injured people were taken to overflow camps. Those in Category I were secretly taken to modules and burned alive, as this seemed the only way humans could die after the Miracle occurred.

The Categories were arbiritarily applied. A Category I could become Category II, should they recover; under this system, Rex Matheson should have been killed, but healed.

Category I
Those people designated as Category I were brain dead or otherwise unable to think or function. In the overflow camps, Category I patients were designated with a red clothes peg and sent to the modules to be burned.

Category II
Category II consisted of those who had non-fatal injuries. In the overflow camps, Category II patients were identified with a blue peg.

Category III
Category III referred to anyone who was healthy. It referred to anyone not in Categories I or II. (TW: The Categories of Life)

Behind the Scenes

 * Esther Drummond jokingly referred to Jack Harkness as "Category Jack" due to his becoming mortal, as opposed to the rest of the planet's immortality.