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) in a companion role and excludes minor roles, cameos, flashbacks, and so forth. Also, the table refers solely to adventures with the respective Doctor. Some companions who appear with two or more Doctors appear in separate tables. The following three characters, all associated with UNIT during the Third Doctor's exile to Earth, are sometimes considered his companions despite appearing irregularly during his tenure. A few of the companions have died during the course of the series. Katarina sacrificed herself by opening her airlock to save the others from the mad fugitive Kirksen, and was blown into the vacuum of space.