'Sense of impending doom'. It means - outside of the context of literal impending doom - that your body has noticed something very wrong but can't identify It. Doctors take it quite seriously.
Madness string 105723
You have to be so precise when you're sending shock waves through a planet. A few degrees of error and you've shot an old folks' home into space. They won't like that at all. Those places thrive on routine.