Thanks for the info!
Here's my take on this:
From what I understand, the bios chip is not initiating the start-up process, which would usually allow us to start up something from USB or from a hard drive.
If I was using a desktop motherboard, I would just unplug the CMOS coin cell battery for about 1-2 minutes, which would reset the bios to the factory default settings.
A surface does not have a CMOS battery like a desktop motherboard. Instead, the surface uses main battery to keep the bios setting (there's always battery levels reserved to keep the bios chips alive, even if the surface says 0%).
So...in theory...if I unplug the main battery internally from the motherboard, the bios should reset.
Problem though, is that the surface devices are VERY difficult to disassemble. There's a good chance the screen will break upon trying to do this: https://www.ifixit.com/Teardown/Microsoft+Surface+Book+Teardown/51972