I tested it out to see and the safety scanner is run from within windows and the offline one from bootable media.
Unfortunately it doesn't seem like the bootable disc can update itself from the boot environment so you'd have to create a new disc/usb each time you need to use it. Also this tool requires a 32 or 64 bit version depending on the OS you're scanning.
Glad the microsoft is finally providing these tools now as well that we used to have to go to 3rd parties for.