The Ending Of Doctor Who Season 4 Explained

"Doctor Who" has to be one of the greatest achievements in science fiction history. Beginning nearly 60 years ago, the series has captivated audiences of all ages as they watched the Doctor travel through time, fight aliens, and go on adventure after adventure. "Doctor Who" did see a setback when it was canceled in 1989, and though there was a 1996 film that attempted to revive it, it wasn't until 2005 that the Doctor came back with a bang. The sci-fi show has become more popular than ever, and there are no signs that it is going anywhere anytime soon. 

One of the most popular Doctors is the 10th, portrayed by David Tennant. Tennant's work has been highly praised, and he stayed on for three full seasons and a handful of specials before Matt Smith took over the role. In the explosive final episode of Season 4, the Doctor faces Davros, the creator of the Daleks, alongside his former companions. In addition, Donna Noble (Catherine Tate) absorbs Time Lord DNA after inadvertently creating a clone of the Doctor, who commits genocide against the Daleks, Rose Tyler (Billie Piper) returns to the parallel world and begins a romance with the Metacrisis Doctor, and Donna has her memories erased when her Time Lord brain threatens to kill her. 

When the Doctor comes face-to-face with Davros, he is forced to see what his companions become while traveling with him. Davros poses a great threat to the universe, and in order to stop him, several of the Doctor's friends step up. Martha Jones (Freema Agyeman) threatens to use the Osterhagen Key to destroy the planet, while both Sarah Jane Smith (Elisabeth Sladen) and Jack Harkness (John Barrowman) are not against using an explosive Warp Star. Davros regards these threats and tells the Doctor that he takes "ordinary people and fashion them into weapons" and warriors. 

The Doctor proves time and time again he is a man who abhors violence, but he knows the truth. Throughout his journey, many people have died fighting for him. The situation this time is even more desperate, with the entire universe at risk. As the Doctor and his friends face off against him, it becomes clear that they have become weapons in a way. They are no longer just traveling companions: they are warriors. Despite Davros' attempts to break the Doctor, his friends show that he has changed them for the better, and they are willing to do whatever it takes to protect, just like the Doctor does.

After the Doctor and his friends return all of the stolen planets, he returns Rose to the parallel world that she found herself trapped in at the end of Season 2. He tells her that he wants his half-human clone — who is full of bitterness and rage — to stay with her, so her influence can make him a better person. Rose asks the Doctor what he was going to say during their last meeting, and he responds, "Does it need saying?" The Metacrisis Doctor whispers the true answer in her ear, and as they embrace, the Doctor sadly looks on and walks back to the TARDIS. 

This bittersweet scene presses home the fact that the Doctor and romance just don't mix. As a 900-year-old-plus Time Lord, he cannot afford to get caught up in human emotions, and as a result, he is forced to put his own interests aside to let his potential romantic interests find happiness. By asking Rose, "does it need saying," he indirectly confirms his confession. However, by not outright saying those words, he distances himself and shows that, even if he may want to show it, love is not something he can freely give. He must keep moving, no matter how painful it might be.

After leaving Rose and the clone Doctor, it appears the Doctor and Donna are off to new adventures. However, Donna begins acting strangely, and it becomes clear that being a human Time Lord Metacrisis is having a painful effect on her. Despite her pleas to stay with him, the Doctor erases her memories of their adventures, their fun, and their friendship. He returns her home and laments the fact that she will never know she was the most important woman in the universe. 

The Doctor just suffered one emotional blow, only to be handed another. With Donna, he relished in her friendship, elated that he could be himself without any romantic strings. However, this scene proves that the nature of his relationships doesn't matter at all. When he gets close, he always ends up in heartbreak, and he always ends up alone. These continuous tragedies have stripped him of his cheerful attitude, and the Doctor realizes that he must be by himself. When Wilf (Bernard Cribbins) asks about his friends, he says, "They've all got someone else. Still, that's fine. I'm fine." For the Doctor, it is better to be alone than to get his hopes up, only for them to end up getting crushed.