I’m in the middle of writing uni dissertation, kept getting a pop up every hour for a restart needed. Decided to update while I was having half an hour break... it’s only on 22% 
So decided I’ll take the dog for a walk now while it’s finishing updating. If I leave the laptop plugged in will it be safe? Not sure what I expect to happen but I’ve always had it drummed in to me to unplug things before leaving.