GM:
Although the rule to which you are referring (6.02(b) comment) refers to a batter stepping out of the box, neither the MLB interpretation, nor the manner in which MiLb umpires are trained require it.
Both MLB umpires and MiLB umpires will invoke 6.02 (b) comment and rule, "that's nothing" and have both the pitcher and batter start the pitch over with no penalty if the umpire judges that the pitcher's action was the direct result of the batter's action, even verbal whether or not he stepped out of the box.
To do otherwise, it has been ruled, is to penalize the pitcher for the batter causing a "balk."