If anyone is interested, I think Maria is inspired by Yuko Moriguchi from Confessions (告白). Similar premise, grieving mother hell bent on the sweetest revenge. Definitely worth a read or a watch, was first a novel and then a movie.
She probably had like an "admin" type passphrase or something that she indoctrinated into Romy to do w.e as a safeguard. Only reason I can think of, considering how robotic she is.