Why do you have to turn around during the APFT?

In my 18+ plus years, this question has plagued me. Ever since basic training, when you are waiting for your turn to do the push up or sit up event, you are waiting in line for your grader, but are told to gave away from whomever is being graded at the time. While this practice has lessened of late, i still see it from time to time. Can anyone explain to me the purpose of this? And if in fact there is a regulation or FM paragraph that covers this? I've looked but haven't found anything. Thanks in advance.