I just fumbled one of the eggs I was going to hard-boil for dinner. It's just a slight crack, but enough that there's a bit of albumen seeping – I definitely can't hard-boil it now.  I have no plans for one raw egg. What's a quick and simple way to use it so it doesn't go to waste? 
If you didn't originally plan on using the egg out of shell, there is no reason you need to do it now. The egg if put in a sealed container can last 2-4 days out of shell according to stilltasty.com.   If you don't plan to use the egg within that time frame then you can extend that time farther by freezing the egg: Can raw eggs be frozen?. 