I believe you can not, because they check your pockets prior to entering the clinical encounter hallway. You can't have anything in your pockets so I assume they won't let you. Just ask prior to the start of the exam or call the testing center.
While I cannot speak for everyone, given the format of the test it's not really a problem. You do the majority of your thinking inside the room with the patient. Once you're outside, you're just regurgitating what you already thought of. I know it's an exam so it's a lot more stressful, but it really should be no different than typing/writing your note in the hospital.
I did not find it distracting at all. This is coming from a person who was distracted for almost all of CK. I think CK takes a huge amount of concentration whereas CS is much more relaxed.