Hi IlanaU,
have you attempted to run the two-button shutdown?
Hold down the + volume button and the power button down at the same time for about 15 seconds. After around 15 seconds has passed, release the buttons and wait for an additional 10 seconds before turning on the device again. It's also a good idea to try the driver pack for the Book, which you can get here.
Hit the download button and get the "SurfaceBook_Win10_160400_2.msi" version. Restart the device after you have installed it.
let us know if it is still stuck.
Kind regards
Hawkie