They figured the false witness was what the teacher was telling them. Just because you learn the answers doesn't necessarily mean you have to believe them.
Your answer isn't clear. Did they supply answers in the exam that they believe to be falsehoods? That would be lying.
Any chance of you addressing that retroviral evidence? If you don't understand it perhaps you should run it by one of your clever daughters to get the rebuttal for me. If you have a valid rebuttal then you'll convince me.