Open the Range
Ranger Utility 10
You keep your distance from an approaching adversary, backpedaling easily away from him.
Personal
Trigger: An enemy moves adjacent to you
Effect: You can shift 1 square and then move a number of squares equal to 1 + your Wisdom modifier. You can't end your move adjacent to the triggering enemy.
Open the Range is a daily power available to rangers at the 10th level.[PH:109]