Stairs

Stairs were a method of accessing areas higher or lower than ground level.

History
The Eleventh Doctor used regeneration energy to heal River Song's hand whilst sat on the stairs in Julius Grayle's house in 1938. (TV: The Angels Take Manhattan)

During the Shoreditch Incident of 1963, the Seventh Doctor used the stairs to escape the Coal Hill cellar. Making pursuit, an Imperial Dalek elevated up the stairs. (TV: Remembrance of the Daleks)

In 1999, the Ninth Doctor ran up the stairs at the Mornington Crescent underground station carrying a "large silver metal ball". (PROSE: ))

At the Vault in 2012, a Dalek nicknamed "Metaltron" seemingly found itself at an impasse when faced with a flight of stairs that Rose Tyler, Adam Mitchell and De Maggio had ascended, with Adam mocking its plight. The Dalek, however, soon began to elevate up the stairs, leaving De Maggio to cover Rose and Adam's escape at the cost of her life. (TV: )

When his aid was sought out by the Emperor of the Restoration, the Tenth Doctor joked that staircases were "the true enemy of the Daleks." (COMIC: Defender of the Daleks)

The British Proto-Daleks were incapable of ascending a flight of stairs. (COMIC: The Dalek Project)

In his first meeting with Missy, the Twelfth Doctor attempted to use the 3W Institute's lifts only to learn that Missy had disabled them. The Doctor instead used the stairs to escape. (TV: Dark Water)

Behind the scenes

 * In the video game The Last Dalek, based on the events of Dalek, stairs appear as obstacles in Geocomtex, which the Metaltron overcomes by equipping an anti-gravity device.