Can you answer this riddle? "10 POINTS"?

during WWII there was a bridge between switzerland and germany, and on the german side there was a sentry tower with a guard in it the guard comes out every three minutes to make sure no body is sneaking in or out and he has strict orders to turn back anyone trying to get into germany and shoot anyone trying to escape germany without a p. there is a woman who desperately needs to get into switzerland and she does not have a p and it would take six minutes to walk across the bridge, and she manages to cross without getting caught. how? (remember the guard comes out every three minutes)