If you want to get up and walk around you have to leave the room. That might be atleast a 3 minute process untill you sit back down. Since you have to get up walk to the door, tell them you want to take an unscheduled break, wait for them to open a folder find your name, have you sign it, then electronically finger print you and then to come back into the room the same process just in reverse.... I was stretching during the test in my chair.
Hope this helps