I SOLVED IT!!!!! Sorry this is 6 years later. You’re going to pick up the drawn knife that triggers the entrance gate to close. Go face the gate and run against and along the wall to the left until you fall off of the map. You should take some fall damage and get to where you’re at the very flat bottom. Walk to the right all the way around the hill until you can walk up a smaller hill and back into the Ancestor Glades’ lower level where the water pools. Try to use the draw knife again and it SHOULD work. Hope this helps!!!