There is a feature in windows 8.1 that makes practically skips the bios, and in some cases may actually skip, it even warned that you will not be able to get into BIOS unless you decide before restart.
This saves a lot of time for people with SSD's, MY pc's bios used to take as long or longer than booting OS.
if you do a search in windows 8 help about setting fast boot and forget the name but you pretty much never see bios read out.
But still try Delete, or F2 if. or F11 for boot menu, then choose UEFI
If this does not work, check you motherboard manual, or online for windows 8 and fast boot.
should lead you to the info.
I have never heard of the shift during restart. I will have to remember that.
And I would try that first.
I only used win 8 a short time and went back to 7.