The man that Desmond replaces in the hatch is called Kelvin Inman; the man in the army that lets Sayid go and gives him some money is called Joe Inman - but they are both the same man.
Penelope's father reveals Desmond's last name when they have a talk in the limo. His full name is Desmond David Hume. David Hume, like John Locke, was an important philosopher of the 18th century. Hume was a Scotsman, just as Desmond is. Both were Empiricists, and Hume was heavily influenced by Locke. This would serve to explain the friendship between John and Desmond on the show, and why Desmond goes along with John's plan to stop pressing the button without having seen the Pearl Orientation tape.
It appears the show's writers have a habit of naming characters after famous philosophers in history. Rousseau is named after Jean-Jacques Rousseau, also of the 18th century, a French-Swiss philosopher of the Enlightenment, whose political ideas influenced the French Revolution. Fleeing criticism in Switzerland, Rousseau took refuge and lived with Hume in Great Britain for a time.
It appears the show's writers have a habit of naming characters after famous philosophers in history. Rousseau is named after Jean-Jacques Rousseau, also of the 18th century, a French-Swiss philosopher of the Enlightenment, whose political ideas influenced the French Revolution. Fleeing criticism in Switzerland, Rousseau took refuge and lived with Hume in Great Britain for a time.
Henry Ian Cusick received an Emmy nomination for Outstanding Guest Actor for his performance in this episode.
Throughout the series, Desmond habitually refers to male characters as "brother". This episode marks the only time he addresses a female castaway (Claire) as "sister."
This two-part season finale was shot over a period of 17 days by two crews simultaneously. It was only completed five days before transmission.