The question of whether she was hoping to whistleblow or expose failings on the unit is an interesting one.
Hypothetically it sounds like a perfect defence, especially if there was anything significant on thise handover sheets as "proof".
However, based on personal experience, it's a very difficult thing to prove, and her defence team might have reasoned thus:
"You are a young and relatively inexperienced nurse. You are trying to build a case against experienced consultants and an NHS trust. They are bigger than you, with almost limitless resources. You have a bunch of handover notes that you shouldn't have. You had a grievance upheld, and they've already doubled down. The crimes you are being accused of are the most heinous nature, extremely emotive, and most people, such as those on a jury, will balk at the idea that such accusations would be made without good and honest reason. If you persist in going this route, your mental health will become the focus of the case, and the real issues will be buried. Based on our experience, the route to go is to maintain your innocence, keep your mouth shut, and the lack of evidence should speak for itself when analysed in a court room setting. From here, anything you do or say will be used against you, and framed as a desperate attempt to get out of charges that you have, in essence, already been found guilty of in the media and the court of public opinion."
Bear in mind there was an embargo on other staff being allowed to talk with her, and an implication of negative consequences if they did, plus laws about discussing an ongoing case that apply publicly and privately.
These situations are nothing like the portrayal of such cases in TV dramas. While we all think we would like to be heros and sacrifice ourselves on principle , when it comes down to it, if our security is under threat, would we? Imagine if a police officer, alone with a suspect, insinuated that if they didn't "co-operate" that dubious material might be found on a laptop or phone, either theirs or a loved ones. Or that the financial authorities might get very interested in a family business. Sounds ridiculous of course, but intimidation is a tool in the authority's box, and if you had no proof of the exchange and nobody believes you anyway, because you are the worst kind of human, a baby killer, where does that leave you?
We have no idea of what life was like for Lucy Letby between her first arrest and her conviction, but we can be sure the psychological toll was huge, hence her zombie like presentation and alleged defensive demeanour in court.
Those who believe in her guilt, despite the huge flaws highlighted in the medical evidence and the case as a whole, willcsay it's no less than she deserves. However, if she is innocent, the horror is incalculable, and not jyst for her, for the bereaved parents. It is Kafakesque on an unfathomable scale.