On Tuesday, under cross-examination by murder accused Barry McCarney's defence QC, 27-year-old Rachael Martin branded her former partner "a complete maniac" and "a f***ing b******"
Martin, from Main Street in Kesh, denies wilful neglect and allowing the baby girl's death.
She agreed in court that she never said "one critical thing" about 33-year-old Trillick man McCarney during hours of police questioning.
McCarney denies sexually and physically abusing and murdering baby Millie at her home in 2009.
The trial at Dungannon Crown Court heard that it was only after hearing of the injuries her daughter suffered "that the penny began to drop" with Martin as to who was responsible.
The defence QC put it to Martin that ''there could not have been a shadow of a doubt'' that Millie was attacked during the five minutes she had gone to buy chocolate.
Martin claimed that her "head was just all over the place" and that she couldn't remember what she was thinking at the time" but that, having heard of what may have happened to Millie, she and her family had decided they "had to keep him (McCarney) at the hospital" until police arrived.
The defence QC questioned why, if that was the situation, she allowed "this very dangerous person" to travel alone with her and her mother on the relatively long journey to follow Millie's transfer from a local hospital to the Royal Victoria in Belfast.
Martin replied that her father and stepfather knew they were on their way to Belfast.
However, the lawyer pressed Martin as to why she "volunteered" to travel with a man "who was a maniac". Martin immediately cut in, declaring: "He is a complete maniac" and adding later that "anything could have happened" on the journey.
Martin was also quizzed in court as to how, if everything she said was correct about McCarney, she had restrained her emotion "in not wanting to throttle" him.
She claimed she did not know how she even completed the journey to Belfast and that, from memory, she did not think she even spoke to him.
I have never protected him.
It was then put to Martin that, by the very next day after Millie's death, she was not going around "calling McCarney a f***ing b******".
"That's what he is," Martin said.
Earlier, she rejected suggestions from her own lawyer that she would have shielded McCarney from the police.
Martin was asked if she'd ever suspected her daughter was being abused and replied "definitely not", repeating the answer twice more when asked if she had turned a blind eye.
She told the court that, up until the night of Millie's death, she had trusted McCarney "100%".
Adding that he never gave her any grounds to suspect him, she claimed he "portrayed himself as a doting father", but that everything changed when she realised what had happened.
At the start of her second day in the witness box, Martin smiled as she and the jury were shown over 300 photographs of the toddler, taken by Martin from mid-October through November up to 7 December - just four days before Millie's untimely death.
The pictures, contained in four albums, appeared to show the mother and daughter enjoying a normal, loving relationship, although several did indicate injuries to her head and finger.
Martin claimed the bruise suddenly appeared after "she was put to bed perfect, and the bruise was there the next morning".
She had previously told the court that Mille burned her finger on a candle while being looked after by McCarney.
The trial continues on Wednesday, when Martin will again be cross-examined.