I put in other little things (the Rassilon comment and the humming a Gallifreyan lullaby) to show how having the baby inside her affects what she says or does.

I noticed that! I thought it was quite funny to think of Martha saying “Oi! I’m having cravings, for Rassilon’s sake. I don’t care about all that.”

And the Gallifreyan lullaby...it almost makes me feel bad for poor Ten that he is so out of the loop as to what is going on.