Ubuntu Security :: Boot Usb On Work Computer ?

I work in a retail store at which there is a computer set up in the corner for customers to browse the stores website on. The problem is that that is all it will let me do. I get board, and want to do other stuff. Once windows starts, it skips the logon on screen and once loaded the only thing that can be done on the computer is browse the stores website.

However, if I unplug the computer I can while its starting up get into BIOS. So here im wondering two things. 1) If I put in the USB, boot from it, and load ubuntu (even though I will only be able to use the default programs as theres no way I would want to install it on the work computer), will I get fired? In other words, is there a way if there monitoring the computers to know what im doing or because its a different OS will I be fine. 2) Alternatively, in BIOS there is an option to disable network administration.

For this my question is the same, if I disable it, do fun stuff on the computer all day, the re-enable it before I leave is there a high change of the network administration catching on to this or no.