main character and plot annoyed me[ spoilers]

Her constant naivity and stupidity when questioned by the police and in court bothered me. Yes, she had a bad background, but now she had a responsible position in a bank, so she couldn't have been that tongue-tied, stupid and uncooperative with the police. Also, why didn't she write more details on a note when she had the chance in the bank, such as where to find her daughter--so police could have gone to the house right away? Also, the thugs would have known that even though she thought she had a microphone, they couldn't see her, so she could write notes or pantomime or stand near something noisy to whisper, etc,etc. What good would detonating the bombs [if they were real] have done the crooks?--they wouldn't get their money and would be in much worse trouble.
Let's say, she had reneged and they then told her they had killed the girl, why would she have gone ahead and robbed the bank for them after that?