The Doctor also realises the sarcophagus Clara and Mrs. Pitt's granddaughter Maisie had found in the storage car is for capturing the Foretold.
The Doctor and chief engineer Perkins realize that the Foretold is draining energy from its victims using phase-shifting technology.
The Foretold, finally released from its duty, offers the Doctor a salute before it disappears into a pile of dust, leaving behind its phase-shifting device.
The episode was primarily filmed in the studio, but the scene with the Doctor and Clara on the planet was shot in Limpert Bay in the Vale of Glamorgan.
Frank Skinner considers himself a die-hard Who fan, and he previously had appeared in the special The Five(ish) Doctors Reboot (2013).
[4] Guardian columnist Dan Martin was positive towards the episode and praised the Mummy, saying, "At last, a proper new scary monster to get us behind the sofa," something he felt had been lacking so far in series 8.
He called it "a triumph of production design matched with imagination," and praised Jamie Mathieson, who was writing for the show for the first time, for blending "cool monsters" and "awkward Tardis dynamics."
He believed that Frank Skinner "started well" as Perkins but more impressive was David Bamber, describing his performance as Captain Quell as "poignant," and praised the development of the relationship between the Doctor and Clara.
He was positive towards Skinner's "genuine love for Doctor Who", which meant he was "practically beaming throughout," and called him "an endearing replacement" for Clara in the episode.
He thought that like the previous episode "Kill the Moon", "Mummy on the Orient Express", had a Philip Hinchcliffe vibe too, and that "'Mummy' is a joy, with excellent production design and a roster of perfectly-pitched performances all adding up to create an enchanting atmosphere," and believed it had a "wonderful mood," which felt like "vintage Doctor Who.
... [The] period costumes helped create a distinctive look and feel, the mummified Foretold was well realised and the repeated use of the 66-second countdown clock injected a real sense of pace and jeopardy.
She remained critical of Clara, arguing that "her poorly conceived and written character fails to charm," despite praising Coleman's acting.
Drawing on his love for the series I could see the influences of many of the previous actors to take on the role," and praised the development of the Doctor and Clara's relationship.
He added that it was "the latest superb episode in a strong season" and that "Peter Capaldi's performance is enough by itself to elevate this story to classic status, but Jamie Mathieson's script provides him excellent support".