Go after her!

You start chasing her down.

Despite your best efforts she slowly opens the distance between you.

You have gone couple of hundred yards when you realize that the path she is following doubles back on your right.

She is fast, but it doesn't look like she is conserving any energy. Suddenly you see her lose her balance and trip, and you make up the distance while she gets back up, but before you can reach her she starts sprinting away again.

This is not going according to plan. You are supposed to be fucking, not running a marathon!