AN/ This fic is just a drabble; the TARDIS' musings on the role of the heart in Rose, the Doctor and herself. Takes place sometime after "Parting of the Ways." Part of my TARDIS 100 series, so it's in the TARDIS POV. The BBC owns all things Doctor Who. Dedicated to Cameron.

The heart is a vital organ. No one can argue with that. It's a muscle that moves blood through the body. All complex living organisms have at least one in some form. It has a steady rhythm, a pulse. When that rhythm stops, you die. It is as simple as that.

The heart is more than a simple biological organ though. In many cultures it is a symbol of love. It is often seen as the keepsake box of emotion. It hides secrets. It can be full to bursting. It can be given away and taken back. It can break.

Rose has a typical human heart. It serves its biological purpose just fine. I know from first hand experience that it serves its emotional purpose as well. She holds a deep love in her heart; a love for her family, a love for life, a love for the Doctor. Her heart is strong, one of the strongest I have seen. She's stubborn, like her parents and she has a lot to give. The Doctor broke her heart when he regenerated, forcing Rose to learn how to heal. She gave her heart to the old Doctor, and now it seems like she's given her heart to the new Doctor, or a good portion of it anyway.

When she leaves, I wonder how much of her heart she will be able to take back?

The Doctor, my Doctor, has a different biology to Rose. One huge difference is the number of hearts. The Doctor has two. When people find that out they're surprised, but at the same time, not surprised at all. Time Lord biology. Binary vascular system. Two hearts beating as one.

Like a human heart, the Doctor's two hearts also serve an emotional purpose. He has come to care very deeply for many people, especially the large majority of his companions. He always faces the dilemma that comes with the ability to regenerate. He lives many lives, his companions only live one. He will live to see them die. They always take a little bit of his hearts with them. I have seen them break time and again, only to be patched up once more. They broke a little each time he had to say good bye to one of his companions. They broke whenever one of his companions died. They broke when Gallifery disappeared.

I wonder how many more times they will break? How many times can he stand to have them broken?

I am a time machine and a space ship, but I am not completely mechanical. I have a heart. My heart contains the fantastic and mighty power of the Time Vortex. This power allows me to preform miracles. Time is not linear for me. I have the ability to see into their minds, but my heart has the ability to see into their souls. If you are willing to sacrifice the life you knew, then my heart can change you. It's up to you to make it a change for the better or for the worse.

My heart also holds emotion. I harbour a very deep love for my Doctor in my heart, as he does for me in his. We need each other, especially now. I also care a lot for the Doctor's companions. I'm very fond of Rose. When her time comes to leave, I shall be sad, like I was when Captain Jack Harkness left us.

I thought my heart broke when the Doctor sent Rose home during the Dalek invasion. He told her then to leave me, to let me die. I knew that it was probably the right thing to do. I thought my time had come.

But then Rose and I looked into each other's hearts and saw that it did not have to be this way. The end did not have to happen right then.

When the time does come however, then my heart will break. When the Doctor can regenerate no more. When the last companion says good bye.

It may not surprise you to know that I'm not looking forward to that day.

Hopefully, it's still a long way off. Each heart beat takes us closer to it, but it should take a trillion beats to get us there.

Lub-dub. Lub-dub.