When you go straight up from the second belay, you come to the overlap/undercling (seen here) with the wavy slab and original route above. For the variation shown in this picture, put pro in the overlap and follow it right, then up and right. The initial traverse move right felt about 5.8. From there, a rest, then maybe 5,7 climbing along the undercling to its end, where it meets the easy gully which takes you up to the standard 3rd pitch belay.