The Face of Boe

The Face OF Boe has apeared (obviously) in 3 episodes, End of the World, Series 1, New Earth, Series 2 and Gridlock, Series 3 However the Face of Boe has been in many other Episodes, as Jack Harkness.

All was revealed in The Last Of The Time Lords, Series 3 When Captain Jack Said "The Face of Boe, they called me.". This also explained how the Face knew the doctor was not alone, he had witnessed the doctor meeting the the master.

At the end of the episode jack also said "What will happen if i live for a million years?". The awnswer is he will mutate into a huge head. But if jack can't die does that mean the face of Boe is still alive, and awoke when the Doctor and Martha had left?