when does the look-back-rule go into effect after a hit batter

[BuggBob]

Kind of a dust-up up here last week. NFHA rules. Batter hit by pitch, ball skipped off the dirt and hit her in the bottom of the foot. She was awarded first base. Batter who is unhurt runs to first. Ball is returned to the pitcher, who is in the circle. When the runner gets to first she wonders off the base. Plate umpire sees this and asks the base umpire dose he have time? No! Plate umpire rules batter out for being off the base (LBR). The AD has asked, when does the look-back-rule go into effect after a hit batter?