Can't exit from UEFI on a tablet

So I work in a computer repair service and a lady showed up with the tablet part of the ASUS Transformer Pad TF103C (she bought it without the keyboard, already used). The problem is that she somehow entered UEFI (and she has no idea how), and now you can't exit. The touch screen doesn't work, it is not registering any keyboard or mouse, possibly because you have to enable it which we cannot do because you need to move around in the UEFI setup for that. Neither my mentor nor me have ever seen a similar problem and we didn't make any progress in a few days already. I will give you a list that we know doesn't work:

• the os won't boot
• you can't just plug in a mouse or a keyboard
• it doesn't register touch
• you can't move inside the UEFI at all (except moving up and down on the same section with the Volume + and - buttons)
• you can't click enter with any sort of button combination even if you should
• computers don't recognize the tablet
• you can't factory reset
• you can't hard reset
• you can't boot an OS from an SD card
• you can't even turn the screen on as you please, it is completely black until you connect a charger, and even then the screen periodically turns on and off
• Any sort of help is greatly appreciated.