Actually, I think it's the sound being heard *inside* the TARDIS that they're referring to in the episode. In the old series that was pretty rare, and throughout the 80s all that was heard inside the ship was that bleep that we heard when River landed it.
Nobody's saying that the noise heard *outside* the ship is a result of "leaving the brakes on"
THANK YOU. That is exactly what I got from it.
And even if it's not the case, WHO CARES?

