Donna had let The Doctor talk her out of warning the citizens of Pompeii when it was "volcano day" but she was not going to let him do that again when they suddenly found themselves on Krakatoa the day before the whole island would disappear in a cloud of lava and ash.
They had been having a lovely tropical holiday, Donna sipping teas made of the native fruits and truly enjoying herself in the warm sun when she noticed the frown on the Time Lord's face.
"What is it now space dunce?" she asked looking over the rim of her latest drink.
"This island," he looked around nervously, "I meant to land us on Java but I miscalculated…slightly…" he broke off as he squinted at the sky.
"Who cares?" she held out her empty glass waiting for the serving boy to refill it.
He pointed, "see that?"
She reluctantly followed his gesture and saw what looked like a large mountain, covered in low wispy clouds, "so? I've seen mountains on misty days before!"
"That's no ordinary mountain, that's Krakatoa. And that's not mist, that's ash."
"You said that was name of this island," she sighed clearly too bored for words at his impromptu geography lesson.
"The island is named after the volcano," he explained patiently, "and in less than 24 hours a massive explosion is going to blow this whole place to smithereens."
She finally seemed to catch on, "what about all these people?"
"All 36,417 of them will perish, and so will we if we don't leave now!" he tried to pull her to her feet.
"You have to warn them, get them out of here!" she protested, refusing to budge.
"I can't, this is a fixed…" he started to say but she leapt to her feet and grabbed him in close by the lapels of his customary brown pin striped suit jacket.
"If you say this is a fixed point in history and you can't mess with it, I'll snap your skinny neck in half!" she growled as she gave him a shake.
He swallowed hard, clearly picturing Donna accomplishing her threat, then in a soft, sad voice said, "but it's true, I can't."
"Then I will tell them!" she hissed and started to walk towards a crowd of people.
The Doctor trotted after her, "Donna, you musn't! You know the rules, as a time traveler you have certain obligations, certain regulations and you must obey them."
"I can't sit idly by and watch them die!"
He watched her stalk away with a mix of emotions, fear that she would alter history and anger at her blatant disregard for the rules, and a grudging admiration for her fierce independence.
Decision made, he caught up to her, scooped her up like a fireman rescuing someone from a burning building throwing her over his shoulder. Then taking off at a dead run he practically threw her into the TARDIS as she pummeled his back.
The whole while she was calling him every name in the book and adding a few he had never heard of as they took off.
"I hate you!" she snarled before bursting into tears.
The Doctor nodded slowly, "I know," he sympathized, "sometimes I hate me too."