I've got this from a collection of sources. It's speculation but I'd bet money on it.
Spoiler
The Doctor likes this new race of Flesh people he's seen created. He likes them so much he wants them all to live (there's a clip online showing this from next weeks episode) - including his own Flesh, the ganger Doctor.
Ganger Doctor gets seriously injured (here I'll say I think Rory attacks him when he goes to war - there's a pic of Rory the Roman Emperor riding his mamouth to Senate in London (ffs!!).
Ganger doctor is put into Astronaut suit to keep him alive.
The 'real' Doctor sacrifices himself...to save himself. Ganger doctor gets real Doctors ability to regenerate. Real Doctor is 'dead' but ganger Doctor is so real he's not a ganger anymore. He's a person in his own right, as was explained in last weeks episode, in no way is he a clone (that would be silly
)
Ganger Doctor gets seriously injured (here I'll say I think Rory attacks him when he goes to war - there's a pic of Rory the Roman Emperor riding his mamouth to Senate in London (ffs!!).
Ganger doctor is put into Astronaut suit to keep him alive.
The 'real' Doctor sacrifices himself...to save himself. Ganger doctor gets real Doctors ability to regenerate. Real Doctor is 'dead' but ganger Doctor is so real he's not a ganger anymore. He's a person in his own right, as was explained in last weeks episode, in no way is he a clone (that would be silly
)