Bases loaded, one out, batter hits clean single to center.  R2 and R3 score easily, the ball is cut off and R1 is thrown out at third for the second out.  On appeal, home plate umpire calls R2 out for missing third base.  I have two questions in this instance.  Is the third out a force out because R2 was forced to third base?  Also, R2's run was obviously waived but should R3's run should have counted if this play was indeed a force play for the third out.  Thanks.

Tom