The monster is a smart monster. He knows that, once you leave the safe circle, he has a higher angular velocity. So, as soon as you pass that threshold, he will start to run around the lake. It does not matter which direction he initially takes, but once moving is committed to that direction (if he were to reverse direction, he would end up, in the future at the same point he was once at, but at a later time, and you would be nearer your goal; he's too smart to let that happen). Once you are outside the safety circle, he will run, and not stop running in that direction.