Rose, the very first episode of Doctor Whos revivalbroadcast 20 years ago todayremains one of the shows finest examples of what it wanted to do and be in the modern era. Its introduction to the domestic life of its latest companion, Billie Pipers titular Rose Tyler, put her story at the forefront, setting a template the next 20 years of TARDIS travelers. Its framing of the Doctor, so mysterious and utterly alien, gave Christopher Eccleston a canvas to deliver what would be a career-defining performance.But above all, in its most enchanting moment, it reminded us that deep down beneath all the newness and modernity of it all, itknew whatDoctor Who had always been about from the very beginning. Doctor Who is about running. Ecclestons very first scene in Rose comes after an opening act that introduces us to Roses life. We see her day-to-day, we see how she interacts with her mother Jackie and her boyfriend Mickey, we see the hustle and bustle and banality of a perfectly ordinary life. Its fast-paced, in so much that its then-contemporary TV, from the swoosh-down from space, through Earths atmosphere, right onto Roses alarm clock rudely announcing the start of her day, to Murray Golds zippy soundtrack punctuating its quick cuts. But everything slows down when Rose goes underground at her department store job, trying to find the missing chief electrician. The music turns creepy, things get quiet and mysterious, slowly ramping up the tension and then ratcheting it up even more when the hordes of shop window dummies littered about in the back spaces start coming to life and talking her. And then it comes, the crescendo: a hand grasping hers, out of nowhere, and one simple word barked out of Ecclestons mouth.Run. Its an electric moment, the smashing open of doors as Rose and the Doctor run through, and, yes indeed, its running down a corridor. But its more than just that classicWho trope at play, its the burst of energy the Doctor represents, to Rose and us as the audience, as he just races into her life. The terror of those dummies, the Autons, clambering behind them, trying to break through as they escape into a nearby elevator. The sudden switch as the Doctor goes from complimenting Rose to an alien coldness as he tells her that the co-worker she was looking for, Wilson, is dead. Everything is suddenly running at a million miles a minute, but not in the way Roses life already was in the episodes opening: its discordant, and weird, and exhilarating, and suddenly dangerous. Everything has shifted with that grasp of a hand and that single word. Its fitting then, that the scene climaxes with the Doctor trying to shove Rose out of his life as quickly as he entered hers with a similar warning, telling her to run for her life as he prepares to blow up her shop and take the Autonsand maybe even himselfwith it. All this characterization, all this mystery, all this energy, its there and gone in just a few minutes, truly punctuated with the violent explosion as Roses place of work goes up in flames. It hits you as the audience as much as it hits Rose, but its also everythingDoctor Who should be in just that tiny fragment of time. Its funny, its scary, its weird, theres a mystery and allure about around this strange hero swooping in and out, and youre left to pick up whats left behind with a simple question: just who the hell is this person? How can you not, as I did 20 years ago, immediately be hooked into this weird and wonderful adventure?At that point, the running down a corridor almost becomes ancillary, even if it is ultimately as fundamental to Doctor Who as all that other emotion. But it shows just how immediately Doctor Whos regeneration so keenly understood itself from the get go: and captured an energy that would sustain it for the next 20 yearsand hopefully many more beyond it. Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, whats next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who.