Companion (Doctor Who) "Face the Raven", but in a subsequent episode ("Hell Bent") her time stream is frozen at the moment of death by the Time Lords so that they can interrogate her about the Hybrid; the Doctor takes advantage of this to save her life, but she remains technically neither alive nor dead, does not age or have a pulse. After her departure as a companion of the Twelfth Doctor, she teams with the immortal Ashildr and travels in a stolen TARDIS. Other companions died in alternate timelines or alternate lives. "Brigade Leader" Alistair Lethbridge-Stewart, "Section Leader" Liz Shaw, and "Platoon Leader"
Companion (Doctor Who) companion, Sarah Jane Smith, together with the robotic dog K-9, appeared in four and two episodes, respectively, of the revived series more than twenty years after their last appearances in the 20th anniversary story "The Five Doctors" (1983). The character of Sarah Jane also headed up a "Doctor Who" spin-off, "The Sarah Jane Adventures", with K-9 until Sladen's death. Another companion, Captain Jack Harkness, is the lead character in the spin-off BBC science fiction programme "Torchwood". Not only have these former companions continued to make appearances on "Doctor Who", they have sometimes been accompanied by some of their own companions