Hmm... I don't think they'd let you talk to anyone during the breaks. It was pretty easy to get things from the locker. I won't worry about it. They can probably wait for you outside the test center but it's a long test...
I ate and drank at every single break, haha It made me less nervous if nothing else. Drank too much coffee though, was shaking all over by the time I got out and couldn't sleep until 3am the next day. Don't recommend it.