About a year before the events on the Express, Moorhouse was involved in a car accident that caused him to suffer regular panic attacks.
At some point, the professor booked a ticket on the spacebound Orient Express. While in the dining car, he witnessed the death of Mrs. Pitt, a fellow passenger, at the hands of the Foretold, though he did not make the connection between her passing and the creature at the time.
Following her death, Moorhouse was engaged by the Twelfth Doctor in a discussion on the Foretold, which the latter had settled on as being the cause of the ongoing crisis aboard the Express. Shortly thereafter, the true purpose of the Express is revealed: a number of prominent intellectuals, including Moorhouse, were gathered to study the Foretold so that an unknown entity could harness its capabilities. Laboring alongside the Doctor and other passengers under the eye of Gus, the train's computer, Moorhouse attempted to discern the Foretold's capabilities before he was selected as its next victim.
As the creature moved toward him, Moorhouse was encouraged by the Doctor to describe its appearance and actions. Though initially accepting of this, upon the revelation that he could not be saved, Moorhouse became belligerent and defiant, attempting to bargain for his life with the Foretold. His words failed, however, and the creature killed him.
Despite this, Moorhouse's work did aid the Doctor and remaining passengers in stopping the Foretold; the panic attacks that Moorhouse regularly suffered caused mental anguish. This, in parallel with medical conditions that affected the other slain passengers, allowed the Doctor to discern that the Foretold was a soldier, augmented by ancient tech, that stalked those with medical conditions and drained them of energy through its seemingly supernatural capabilities. With this knowledge, the Doctor stopped the Foretold by 'surrendering' and releasing the soldier from its service, allowing it to die and the remaining passengers to be freed. At the last moment before Gus self-destructed the Express, the Doctor used the Foretold's teleporter to evacuate the survivors; Moorhouse's body was presumably left behind and destroyed in the explosion that followed. (TV: Mummy on the Orient Express)