Adelaide was a tiny loli when the Daleks stole earth in 2009. Given the opportunity to exterminate her, the Daleks refused, recognizing that she was a Potential Companion and thus her tragic death was a fixed point in time. This prediction came true when she grew up to be the MILF in charge of Bowie Base One on Mars. Her group encountered a virus the Ice Warriors had frozen in the ice caps, got picked off one-by-one, and was destined to blow the whole place up and thus save the earth from the virus. Instead, the Doctor saved her and two of her least important allies, declared himself the Time Lord Valeyardious, and prepared to remake time as he saw fit, starting by undoing the destruction of his people in the Time War. To prevent this, Adelaide blew her brains out, convincing Ten he'd gone too far, and that he should never use his magnificent time machine to drastically change the course of history. Immediately afterwards, he got in his time machine and teamed up with his once and future selves to undo the destruction of his people in the Time War, drastically changing the course of history.