User blog comment:IamJakuhoRaikoben/Chapter 345: Someone's Voice, Review./@comment-77.195.192.248-20130728093956/@comment-7418318-20130728111307

She already defeated and humiliated Lucy publicly and if it hadn't been for Chelia and Wendy, Lucy would even have died, juding from Porlyuscias comment. Minerva has no reason to proof that point a second time. If there is anyone who Minerva has a grudge against it's Erza.

Also Minerva seemed to have quite a lot of fun torturing a bound up and thus helpless Milliana and an already unconsious Lucy, so I don't see why torturing a childifyed Lucy would be "less funny" for her.