There is an orecart attached to the end of the winch.  A pull of a lever brings the right gears in contact with the Ever-Spinning Wheel and the cart rises to the upper floor.  Another pull, and the winch swings it over the solid floor.<br/><br/>Chay gets aboard with both his longsword and his fighting knife out, and stands in a wide, stable stance in the middle, looking all around.  Cersei works the crane controls and lowers him down as fast as she can comfortably manage.  He hops out and takes up a position nearby, turning slowly to keep as many of the tunnels in view as possible.<br/><br/>One quick winch trip, and the platform is now ready for Koh.<br/><br/>((Let's say Koh has been watching Cersei at the controls, so he knows how to operate the winch from below.))