Test drive at the dealer’s after five minutes finished by the dealer because ride is not insured?

I have a question about test drives or about the duration of standard test drives. I am currently looking for a new vehicle and have already made some test drives in my life. The last dealer where I bought my car half a year ago let me drive two hours on my own on two different days. I then bought the car. Now I looked at an Audi A6 built in 2004 for interest, among other things. d agreed an appointment for a test drive, because I was really interested. During the actual test drive, an employee accompanied me from the dealer. After five minutes, however, the employee said that I should drive to the right, that this is enough now, because one generally only allows five minutes test drive, because the test drive is not insured and if something happens with me as a buyer at the wheel, then one remains as a dealer on the damage. Can such a thing be? I’ve heard this for the first time. Is there any difference in what liability the dealer has to his insurance policy?