About reading the question loud:
No you are not allowed to read aloud in the Prometric Center. They will give you a warning if you do so. Therefore the best way is to train yourself from now to practice not reading aloud, instead use the mouse cursor to point and follow the words and rows of the questions and learn to read (whisper) to yourself. For more details please read here http://www.usmle-forums.com/usmle-a...ize-online-usmle-qbanks.html?highlight=cursor
About the Noise:
You will be sitting in a cube that's closed from three corners but you can still get the noise from the other test takers and therefore they provide you ear plugs and headphones so that you can block out the noise.
The noise that's coming from other students taking the exam is not that they are reading loud but because they may be typing on the keyboard and using their mouse clicks.
Noise can also come from AC conditioning and the outside environment if the center is not adequately insulated.