The Doctor was just supposed to be passing by, he should just pass by. But, he felt what seemed like a magnetic pull toward room 11. It was his room.
"No. No. No. No. No." The Doctor told himself. He shouldn't look in the room. He wanted to, though. Room 11 contained his biggest, deepest, darkest fear that lied at the bottom of soul. A fear that the power of time and space could not erase. What had he seen, come to know in all of time and space that scared him more than anything else?
The Doctor's mind rambled and thought and considered and reconsidered. He didn't know. He needed to know.
In a second he had opened the door and peered inside.
There he saw it. In the middle of the room. His ultimate fear.
Rose Tyler, her perfect form lying dead because of him. Not an ounce of the life and strength she once had left in her. Rose was dressed in a long black dress with a sweetheart neckline, black heels and her curled hair, blond as ever strayed to the side, covering up some of the blood. Her broken body was covered in deep scrapes and cuts.
So, this was his biggest fear.
"Of course, who else?" he whispered.
Even after all these years had passed by, he still loved Rose like the day he'd met her. And, it would always hurt to miss her. In a thousand years he'd never loved anyone more than Rose Tyler, so yes his deepest fear that he would never be able to deny to himself was her untimely death, and it being his fault.
But, he knew somewhere, sometime he was protecting Rose Tyler with every last breath and bit of strength he had. The Doctor shut the door and continued on chuckling to himself.
"Rose Tyler." He thought to himself, the girl he'd never be able to rid his hearts of.