Please take a look of the deck plan's of the MSC Opera, to see where the cabins are located;
I don't think any of them is located "under" the water, actually
If you're looking at the deck plans, you will see these symbols:
It will tell you if the extra beds in the staterooms are bunk beds or a sofa bed. This is what will be the 3rd and the 4th bed.
I will also recommand you to write your Post's with small letters. CAPS LOCK is definated like "shouting", and small letters it's mutch easier for us to read.