Another one

[chapmaja]

Here is the situation.

2 out, 3-2 count on B3. B3 swings and misses, F3 drops the pitch. B3 makes no attempt to run to first, and starts walking toward the first base dugout.

The question is at what point do you call her out.

This was a discussion on another board.

Personally, as long as she is moving, I'm not calling her out until she does something else to prove she has no intention of advancing, such as entering dead ball territory.

What do other umpires use as a guide for making a decision on this.