Disable Internet Connections Without Privilege?

I currently am forced to have to use public computers where all the security is on the lowest security options ergo meaning there is a warning stating: "to not expect any privacy, and therefore any information used or stored on library computers may be accessed by others."All of these are unadvisable, as I used to run corporations where we were adament in regards to protecting the privacy and rights of others. How with their being a warning "I do not have access to administrative details," can I disable all network connections, as well as disabling the internet to guard my privacy? The system I am speaking of is known as "CASSIE," and previous to the city over seeing all aspects of IT, I had no problems. Now essays have been changed, I have had pertinent details, i.e. how to pass the bar, mastering the essay portion of the bar.... and all of these have been erased from my USB's along with many other pertinent files.