Batter Overrunning

 
The batter (B1) grounds to the shortstop, who fields the ball and throws wildly to first base. B1 tags 1st base and then runs past the base and 15 feet down the foul line. When B1's coach yells that the ball is overthrown, B1 takes two quick steps toward 2nd base -- but then rethinks, and starts to slowly walk directly back to 1st base. The catcher retrieves the overthrow, throws to the 1st baseman, and B1 is tagged as he slowly walks back to 1st base. Should B1 be called out?

Call
A batter-runner who is advancing to first base on a batted ball may overrun first base and not be at risk of being tagged out - as long as he immediately returns and he makes no attempt to advance to 2nd base. Turning towards 2nd base does not in and of itself constitute an attempt to advance to 2nd base. However, making (in the umpire's judgment) a "baseball move" to 2nd base does constitute an attempt to advance. The batter-runner loses his protection and is at risk of being tagged out by the defense.
 
In the play described below, the batter-runner has lost his protection and was tagged for an out.