You Make the Call

Question - with a runner on first and two out, the batter hit a ball through to the outfield. The runner from first came all the way to third and started down the line toward home. Her coach saw the ball coming in quickly so called her back to third. She turned to come back but bumped into the third baseman, the ball was still at second base. The base ump extended his arm to indicate that the runner had been obstructed. The base coach then told her to run home, assuming the obstruction call gave her free passage. The opposing team threw the ball home and tagged her out. The call was protested but to no avail, the runner was out.  Why?
 
Answer - the Obstruction call may be one of the least understood. It gives you free passage to the base you are headed toward. If you try to advance any further you are again liable to be tagged out. In this case the runner was between third and home but was headed back to third. She gets third base, by turning and going home she forfeited her protection and was again "in play".