Ruby's Hidden Memories Lead The Doctor To Trapping Sutekh
In "73 Yards," Ruby's solo adventure leads her to living a full life without the Doctor, with the Mystery Woman close behind. While this is harrowing and terrifying, it did lead to Ruby possessing the necessary information to fight Sutekh and win in the end. At the beginning of the episode, before the Doctor disappears, he mentions Roger ap Gwilliam, a man who would one day become the most controversial prime minister of all time.
With the name ringing in Ruby's ears as the final conversation she had with the Doctor, Ruby remembers the name when he does eventually rise to power. In the course of the episode, Ruby finds a way to infiltrate Gwilliam's inner circle, and uses the Mystery Woman in her favor to get rid of Gwilliam. Considering everyone who speaks to the woman runs away in terror, completely writing off Ruby and trying to get as far away as possible, Gwilliam flees and resigns from his position before making any significant changes.
"Empire Of Death" Can Explain A Mystery From "73 Yards"
Despite this connection, the mysteries of "73 Yards" are not completely resolved. Questions about how the mystery woman first appeared, what it meant that Ruby is that woman, and what she says to cause people to run all remain after the season's finale. However, "Empire of Death" does conclude one mystery. The woman always stood exactly 73 yards away, never coming closer, and no matter where Ruby was, she only ever came to that point.
In "Empire of Death," the Doctor explains to Ruby that the Tardis has a perception filter that extends to 66.7 feet. Ruby instinctively knows that this distance is equivalent to 73 yards, which is the exact distance the mystery woman always kept from her. This strongly suggests there was a link between the old woman and the TARDIS, which meant she could not come within that range of Ruby.
Does Ruby Remember The Events Of "73 Yards" Now?
While Ruby may have forgotten the exact details of "73 Yards," it is clear that the events left an impression on her mind which has not disappeared despite that reality seemingly fading away. Her knowledge of the specific distance, and her memories of Gwilliam allude to Ruby still having a deeper, subconscious awareness of what happened to her, even if that reality no longer exists. While this likely points to a clear connection, the finer details about why, and how remain a secret that may be revealed in season 2, or beyond, depending on where Doctor Who's story goes next.
Time is not a clear and definite linear system, and this becomes even more true for companions of the Doctor Who jump between realities and points in time and space. Beyond the regular dimensional travels of the Doctor which see him and his companions explore the vast expanse of space and the ends of time, there have also been several times when the Doctor crosses into other dimensions and realities. Ruby is definitively on Earth, in the present day, but that does not mean she wasn't in the past, future and even alternate realities too.
