I never said to do it while it’s in the middle of changing stuff, but if you just booted you can turn it off and nothing will happen because worst case it will just be downloading without installing, as someone else mentioned, once updates are installed you can even turn off without applying updates if you want and you can also tell it to only download and not install unless you tell it to or not download at all.

I did that once, the registry stopped working. Turns out it can’t boot without that