In ‘A Good Man Goes To War’ we are introduced to Lorna Bucket. Having once met the Doctor she joined the Church so that she might meet him again. When she does she is dying and realises the Doctor doesn’t recognise her. The Doctor denies this claiming that he remembers everyone but after she dies admits that he doesn’t know who she was.
This is a sad, touching scene highlighting that the companions we see on screen are the lucky ones. They are the ones that get the Doctor’s attention and for the most part survive.
Characters like Lorna, Katarina (‘The Myth Makers’ to ‘The Dalek’s Master Plan’), Lynda (‘Bad Wolf/Parting Of The Ways’) and Rita (‘The God Complex’) are the unlucky ones who could have been a companion but the Doctor either failed or forgot about them.
There are several ways that this scene can be interpreted.
THE DOCTOR LIES
The Doctor did meet Lorna but really doesn’t remember her. The fact that Lorna almost instantly knows that he doesn’t recognise her could be because it wasn’t the 11th Doctor she met. Knowing that he has since regenerated she understands that their encounter could be in his distant past.
The Doctor has had many adventures and met so many people that it is understandable that he doesn’t recall them all. For them it could have been the most important day of their life while for the Doctor it could be an average day for him.
This does allow original PCs to be paired up with past Doctors. They might consider themselves a true companion but if they were to meet a later incarnation that Doctor might not remember them at all.
IT HASN’T HAPPENED YET
Rather than an encounter in the past some incarnation after the 11th will eventually find themselves in the Gamma Forest and meet a young Lorna. This adventure would have shades of his relationship with River Song, where he knows her eventual fate.
This could be an interesting adventure to revisit how the universe views the Doctor. Lorna’s people considered the Doctor a mighty warrior. Would the incarnation that arrives there live up to his legend or try to change their perception of him?
Lorna says that she only met the Doctor once but she might still end up travelling with him, only to have her memory wiped (just as the Time Lords made Zoe and Jamie forget everything but their first adventure with the 2nd Doctor).
By this point the universe has already been rewritten multiple times (more if the Kovarian Chapter did succeed in subtly altering history) so the Doctor that Lorna met might not be this version of the Doctor (that is he hasn’t experienced those events).
Some Time Lords might not concern themselves with such continuity problems, concentrating on moving forward, but what if they decide to look back? Would this Doctor be satisfied that this alternative past version of himself did the best he could? Might he travel back along his own timeline to check?
This also means that time travellers might encounter those who claim to have a past history with them when they actually met a different version of them. This could be the first clue a PC gets that reality has been rewritten.
LORNA IS LYING
Remember that this episode revealed that the Church were carrying out a very long plan to turn Amy’s daughter, Melody, into an assassin to kill the Doctor. Lorna could have been just another part of their plan.
Rory quite rightly points out that Lorna is part of an organisation dedicated to eliminating the Doctor, reason enough not to trust her. Lorna could be brainwashed or have memories implanted to appear loyal to the Doctor, hoping that he’d take her in (where she could either betray him or destroy the TARDIS itself).
Something went wrong and she ended up sacrificing herself. You might play out an alternative version of events where she survives (just as Strax did) only for her true nature to be revealed at a later point.
The Church might attempt to do the same thing again, planting a potential companion in the Doctor’s path who also claims to have a past history with him. If the Church didn’t vary their cover story this plant might tip their hand by claiming this also occurred in the Gamma Forest.
CLARA MARK II
Lorna has a significant impact on the events of this story. Due to her betrayal of the Church she saves the Doctor’s companions and arguably the Doctor himself as a consequence. She even gives River Song her name thanks to the quirk of her language.
Here she dies to save the Doctor but what if the Doctor were to meet another Lorna on another world? One that has no memory of the Doctor but ends up saving his life at the cost of her own?
This could mean that she is in a similar situation to Clara. At some point in the future she too will enter the Doctor’s timeline, saving multiple incarnations. Since ‘The Name Of The Doctor’ might have been altered due to the events of ‘The Time Of The Doctor’ Lorna could take Clara’s place in the new version.
It also stands to reason that the Doctor will have to die permanently at some point, leaving a time scar. As history is changed and the date and circumstances of this certainty keep altering there could be a continual influx of guardian angels protecting the Doctor throughout his life.
THEY’RE ALWAYS BRAVE
One truth that we can take away from this is that all of the Doctor’s companions (whether it be a single adventure or more) show courage. He might not remember them but he can still hold them in high esteem.
Davros accused the Doctor of turning his companions into weapons but it could be argued that he makes them brave. It doesn’t matter if they do ever encounter him again, they were still heroes.
Lorna dies here but her character and her actions suggest this isn’t the first time she helped others. There could be countless people like her, who only met the Doctor once, but have been saving the world ever since.
This could be a good way to link characters together in a campaign that doesn’t include the Doctor or other Time Lord. The fact that each one has previously met the Doctor means that they have the qualities needed to carry on his work, alone or together.