I saw STID last night and have been musing on a few things, a couple of which deal with the planet of Nibiru at the start of the film.
If you've not seen the film, please turn back now.
Firstly, why is the Enterprise
underwater? How many times has a ship successfully conducted observations and away missions from standard orbit? Why would they need to complicate the entire operation and risk exposing the ship to the inhabitants by taking it all the way through the atmosphere and then into the ocean? It baffled me.
Secondly, the crews actions on the planet (stopping the volcano) is in itself a violation of the Prime Directive, as they are interfering with the natural development of that species. As unpleasant as it may be to allow a race to die, had the Enterprise
not been there the volcano would have erupted and that would be the end of them, by stopping the volcano they interruped the natural development of the native species--which is far worse than them just seeing a starship rise from the water.