Infected timeline (Interference)

An infected version of the Doctor's personal timeline was created when Faction Paradox infected the Third Doctor with a biodata virus. In this version of history, the Third Doctor died of a gunshot wound incurred on the planet Dust instead of radiation poisoning while fighting the Eight Legs. (PROSE: Interference)

The Edifice, a half-dead future version of the Doctor's TARDIS, contained the paradox, holding both timelines in superposition and allowing the Doctor's life beyond their third incarnation to remain mostly stable. Things finally came to a head with the Doctor forcing a choice between the two versions of his life, purging himself of the biodata virus and restoring the Third Doctor's original death. (PROSE: The Ancestor Cell)