This section's awfully stubby.
The Twelfth Doctor mentally swore "by the Rivers of Rassilon" when exasperated by his earlier self's antics regarding their disagreement on proper TARDIS control console interiors. (PROSE: Twice Upon a Time [+]Paul Cornell, adapted from Twice Upon a Time (Steven Moffat), Target novelisations (Target Books, 2018).)
Behind the scenes[]
- The reference to the Rivers of Rassilon in Twice Upon a Time [+]Paul Cornell, adapted from Twice Upon a Time (Steven Moffat), Target novelisations (Target Books, 2018). is too fleeting to clarify whether the Rivers somehow constitute Artefacts of Rassilon, or if the similarity in naming scheme to such items as the Harp of Rassilon is merely coincidental and the Rivers are mundane bodies of water merely named after the Time Lord dictator.