If by answering all the questions truthfully it may take the focus off her and redirect the investigation's focus on to who actually did take Madeleine don't you think for Kate that was worth a punt ?
She'd answered all the questions up until arguida time.
If what she describes in her book is accurate about the lawyer disappearing for a while and then hinting that it might be in her interest to consider confessing (and if that isn't accurate, I've no doubt that we'd have heard all about it), then I'm fairly sure I'd have been suspicious as well. I don't have the book to hand, so I can't cite the passage.
Some of the questions seem fairly commonplace, e.g. what did she see upon entering the flat, but I find a number of others difficult to answer in a way that couldn't be "misunderstood".
--- Asked about her professional life, and in how many hospitals and in which she had worked, she did not respond. Being a doctor, and asked about her speciality, she did not respond. Asked about if she worked in shifts, in emergencies [the emergency section of a hospital] or other services she did not respond. If she worked every day, she did not respond. Asked if at a particular time she stopped working and why, she did not respond. She'd trained as an anaesthetist, prior to retraining as a GP.
--- Asked whether or not it is true that the twins have difficulty sleeping, that they are restless and that that causes her uneasiness, she did not respond.
--- Asked whether or not it is true that at certain times she felt desperate [driven to despair; angered; exasperated] by the attitude of the children and that that left her much disquiet [unease], she did not respond.According to extracts from her diary (assuming that were accurately described), the twins did have trouble settling down on occasion, and there was a toddler tantrum incident in the car one day.
I'm aware that she wouldn't have known the questions in advance, but I have no problem imagining how answers to those (and numerous others) could feed into a prosecution case.
In her view, they'd stopped looking for her anyway. If she'd got banged up on remand (and Gerry would probably have been as well, IMO), how on earth could they carry on searching for their missing child?