Howling:Timelord Biological Metacrisis
The Doctor and River Song both made it quite apparent that excess regeneration energy left in the few hours in their post-regeneration states allow them to regenerate from at least a reasonable amount of injury at what appears to be no cost to them.
Given the number of Gallifreyan villains who has appeared, if the metacrisis cloning process done by the 10th does not cost a regeneration. This mostly harmless technique would allow them extra regenerations simply by cutting off parts of themselves to carry around right after a regeneration and use them at their next regeneration.
The implications seem to suggest that the Meta-Crisis Doctor did cost a regeneration.--218.189.39.199talk to me 09:21, August 26, 2012 (UTC)
The Doctor's use of his severed hand to abort the regeneration was (as the dialog indicated) something he knew about quite well. It's entirely possible that "Gallifreyan villains" -- & perhaps non-villains -- have used that technique before but we simply didn't see it on screen. Until the revived series, we didn't see any regenerations except the Doctor's. Even Romana's actually took place off-screen, although we did see some of the bodies she tried on (& asked the Doctor something not dissimilar to "Does my bum look big in this?").
The biological metacrisis wasn't that aborted regeneration. It was what happened in the TARDIS, as she was being destroyed in the core of the Crucible, between the energy-laden hand & Donna Noble. It was that, not the aborted regeneration itself, which gave rise to the "clone" of the 10th Doctor. That (as the dialog again indicated) was something new to the Doctor's experience, although he quickly worked out what had happened -- he always has been good at that sort of fast thinking and it might have been something he knew of as a theoretical possibility.
The metacrisis was made possible by the aborted regeneration but wasn't an inevitable or even a likely result of it.
It's also worth noting that the metacrisis occurred only a short time after the aborted regeneration, so we have no way of knowing how long the hand would have retained enough energy to make a metacrisis possible. My own guess would be that it wouldn't retain it long -- maybe about the 15 hours or so that regeneration energy persists at a high enough level to allow the repair of serious injury. Retaining it for a long time would increase the chances of a subsequent metacrisis & make it unlikely that that would be something new to the Doctor.
You seem to be confusing two distinct events & drawing a wrong conclusion as a result. --89.241.74.244talk to me 16:06, August 26, 2012 (UTC)
