|is there any 'backdoor' way i can get in to access the hard drive and copy files over to a usb?|
Well, that'd hardly be secure, wouldn't it?
If you know Linux, you could get a Live Linux CD with USB and NTFS support.
You could download a bootable CD to reset the admin's account. Be prepared to explain to the IT staff why they can't get into their laptop when you return it.
You could remove the drive, and install it into a computer you have control over. This is probably the easiest way if you have the tools.
You could just ask the IT staff; normally they aren't dicks about these things (and even if they are, they usually oblige).