Tired
The TARDIS sped through the universe. The sounds and jerking of the time machine and the Doctor's manic expression couldn't distract Martha today. Every time Rose was mentioned she got lost in a wave of jealousy and bitterness and hatred, and the Doctor did like to bring up Rose an awful lot.
I'm tired, Martha thought. She was tired of constantly feeling jealous, she was tired of being held at arms length from the Doctor (did he do it to spite her, to mock how she felt about him? Sometimes the Doctor reminded her of those senselessly cruel men who like to keep pretty girls around in order to tear them down). She was tired of hating someone she didn't know. She was tired of loving someone she didn't know too.
They were flung around the TARDIS console as the Doctor dragged them through time. It was a beautiful chaos, like a burning city, and Martha knew that this was the beginning of the end. She couldn't go on like this. It would destroy her.
