Doesn't look back rule apply here?

[mg43]

This occurred at a high school varsity game last weekend. There were 2 outs and a runner at 3rd. Batter was walked. Catcher immediately threw the ball to the pitcher in the circle. Batter touched 1st base and, without breaking her stride, proceeded to 2nd. The pitcher threw to 2nd to get the 3rd out. After the throw was made to 2nd, the baserunner stopped 3/4 of the way to 2nd and ran back to 1st as the 2nd baseman chased her. She reached 1st and was called safe. Of course the baserunner at 3rd scored.

Should the walked batter have been called out as soon as she stopped and made her move back to 1st?

Thanks for your help.