The Brink of Death (audio story)

 was the last full cast audio story in the The Sixth Doctor: The Last Adventure audio anthology released in 2015 by Big Finish Productions. It serves as the final chronological story for the Sixth Doctor played by Colin Baker, filling in a critical missing piece of the Doctor's existence and leading directly into the 1987 television story Time and the Rani.

It is prominent for depicting the events leading up to the Sixth Doctor's regeneration into the Seventh Doctor for the first time on performed media with the original actors, and the second attempt overall, following 2005's Spiral Scratch.

Publisher's summary
The Doctor and Mel face the final confrontation with the Valeyard - and the Doctor must make the ultimate sacrifice.

Plot
to be added

Cast

 * The Doctor - Colin Baker
 * Melanie Bush - Bonnie Langford
 * The Valeyard - Michael Jayston
 * Genesta - Liz White
 * Coordinator Storin/Nathemus 1 - Robbie Stevens
 * Lorelas/Nathemus 2 - Susan Earnshaw
 * The Seventh Doctor - Sylvester McCoy

Continuity

 * Another version of the Sixth Doctor's regeneration posits that he absorbed chronon energy in the Spiral Chamber. (PROSE: Spiral Scratch)
 * The Doctor toasts the companions of his incarnation: Peri, Mel, Evelyn, Flip, Mila, Constance and "all the others". The Eighth Doctor would do similar prior to his regeneration. (TV: The Night of the Doctor) Interestingly, this regeneration was also depicted long after Paul McGann, the actor playing that incarnation of the Doctor had left the role on television.
 * While in the thralls of regenerating, the Seventh Doctor tells his predecessor that it is "far from being all over". (TV: The Tenth Planet)
 * The Sixth Doctor is the second of three incarnations of the Doctor to perish from severe radiation exposure, and also because it was an act of self-sacrifice. The Third Doctor let himself be exposed to radiation from a large concentration of Metebelis crystals to seek audience with the Great One and eventually succumbed to it after ten years of being stuck in the Time Vortex while unable to pilot the TARDIS in his deteriorating condition (TV: Planet of the Spiders), and the Tenth Doctor would later put himself in the path of 500,000 rads when Wilfred Mott could not escape a booth about to be filled with radiation unless the Doctor switched places with him to unlock the booth from inside the machine when touching any of the controls would set off the radiation. (TV: The End of Time)
 * The Sixth Doctor's choice to avoid going to Lakertya but ending up going anyway, resulting in his death and regeneration, parallels how the Eleventh Doctor wished to avoid Trenzalore when he learned of a prophecy about his downfall occurring once he went there, but eventually needed to, remaining on the planet for so long he began dying of old age and regenerated with the help of the Time Lords. (TV: The Name of the Doctor, The Time of the Doctor)