[edited from support email]
If I understand correctly, there are some limitations in creating skip patterns for questionnaires. Mainly that you can only skip in a linear fashion based on a current response. Thus say you have 10 items in a questionnaire and you wanted 1-4 answered. Then based on their answers to 1 or more questions you might say:
If item 2=0 and item 3=0 go to item 6
It seems you couldn't do this in MediaLab, either using two items to make a decision or inserting a skip that refers back to previous items.