You can make the a mistake on a driving test, it might not be marked down at all..... it might be marked as just a minor driving fault ..... or it could be marked as a serious or dangerous fault. The mark will be given on the whole build up to the situation.... ie, what you as the driver did, what any vehicle nearby did, was there any other vehicle or pedestrians put as risk ? The list is endless.... remember the examiner MUST GET IT RIGHT.