8-4-1   The batter-runner is out when:

(g) he runs outside the three-foot running lane (last half of the distance from home plate to first base), while the ball is being fielded or thrown to first base; or This infraction is ignored if it is to avoid a fielder who is attempting to field the batted ball or if the act does not interfere with a fielder or a throw.  The batter runner is considered outside the running lane lines if either foot is outside either line.