103 was a number.
While being chased by the police, Lin was driving at 103 miles per hour. (TV: Resolution [+]Chris Chibnall, Doctor Who New Year Special 2019 (BBC One, 2019).)
103 was one of the "random" numbers the virtual versions of Nardole and Bill Potts chose when prompted by Nicolas to demonstrate that they were in a computer simulation. (TV: Extremis [+]Steven Moffat, Doctor Who series 10 (BBC One, 2017).)