Application of the lookback rule

[BratzCoach]

Last night the following situation occurred during a 14u game:

With a runner on 2nd and 1 out, the batter hit the ball cleanly into the outfield. The runner on 2nd rounded 3rd and headed home. The center fielder threw toward home, but the pitcher cut off the ball as the runner was going to score. As the batter rounded 2nd base, the pitcher stepped in to the circle, and on to the pitching plate.

The batter stopped about 6 feet off off of 2nd base, between 2nd and 3rd, and stood there for a good 5 seconds before walking back to the base. The pitcher did not raise her arm or make any kind of movement toward the batter.

When I questioned the umpires as to why they did not call the runner out due to the lookback rule, they told me that the runner could take as long as they wanted to to decide which way to go, as long as they held still. My understanding is that the runner must immediately commit one way or the other, and that's the way I've seen it called in HS ball.

What is the correct application here?