This photograph is literally only possible to get if a few things happen.
1, You get up at 6:30
2, You have a wetsuit, it gets super cold.
3, You have an underwater housing. Impossible to not get a camera wet.
4, You go in October in the two weeks where the sun lines up with the cave like this perfectly.
5, You have a 16-55mm lens for it to create this light effect.
6, The weather conditions are perfect.