Jasmine, the user will not be able to boot to safe mode when the system is like this. The machine simply boots to the UEFI settings page and nothing else.
So this issue popped up for me the day they announced the Surface Book 2. I have managed to get around it. I think my issue is related to batter power. When it gets drained, it has to charge to a certain
percent before it will get past the UEFI screen. What this percentage is I don't know, and I'm not 100% sure if I'm even right.
All that being said, to get mine work I have popped the tablet off the base and started that way. I think by default the surface book uses the base battery first. Sometimes that isn't enough and I have
to plug the power cord into the tablet and let it charge for about 10 minutes and then it's good to go.
I'm currently running a battery test to see if I can narrow down the issue.