[And now they're back to the same argument before. Obviously the Doctor was not listening.]

Sir. This is not the universe you are used to. Tidal waves are the point. That is why we are sent places: to change their courses, preferably for the better. This universe can accommodate what we do. We've seen proof of it, in that we have visited the same Jaunt locations multiple times, and while things were changed, sometimes drastically, the universe remains intact.