Audition

The Fifth Doctor considered the auditions for a new companion to be worse than Daleks, Cybermen and Ice Warriors put together. He once attended one conducted by a director who instructed the five auditionees to scream loudly. (NOTVALID: Doctor Who? 75)

The Sixth Doctor and Melanie Bush once looked in on Cyberman auditions. They involved John Nathan-Turner watching as the heads of those auditioning were blown off by a shotgun. (NOTVALID: Doctor Who? 125)

William Hartnell, Patrick Troughton, Jon Pertwee, Tom Baker, Peter Davison, Colin Baker and Sylvester McCoy all went through auditions to get their roles as incarnations of the Doctor. (NOTVALID: Ever Wondered What Happened At.. The Auditions For The Seven Doctors?)