Chaos (Fish's Sky)
They should have had one person always staying in one place and facing only one direction not moving. Then withdraw from the furthest in and watch that one person so they can estimate in what direction to go and correct it in case they stray away from it. Once the furthest in is outside then go to next furthest and have him withdraw with the same tactic. Would also work if the person outside is gone since they can just use the direction the one person is facing as a sort of compass.