In `` The Sound of Drums '' ( 2007 ) , a flashback shows the Master at the age of eight , when as part of a Time Lord initiation ceremony he is taken before a gap in the fabric of space and time known as the Untempered Schism , from which one can see into the entire Vortex .
In `` The Sound of Drums '' ( 2007 ) and `` The End of Time '' ( 2010 ) , a flashback shows the Master at the age of eight , when as part of a Time Lord initiation ceremony he is taken before a gap in the fabric of space and time known as the Untempered Schism , from which one can see into the entire Vortex .