in the unlikely event of

in the unlikely event of (something)

If a very improbable outcome turns out to be the case. I wouldn't worry too much, but in the unlikely event of unemployment, you can always come live with us for a while. In the unlikely event of me winning the lottery, the first thing I would do is travel to Jamaica.
See also: event, of, unlikely
Farlex Dictionary of Idioms.

in the unlikely event of something

 and in the unlikely event that something happens
if something—which probably will not happen—actually happens. In the unlikely event of my getting the job, I'll have to buy a car to get there every day. In the unlikely event of a fire, please walk quickly to an exit.
See also: event, of, unlikely
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • in the unlikely event of (something)
  • in the unlikely event
  • in the unlikely event (that) (something) happens
  • unlikely
  • a ragged colt may make a good horse
  • colt
  • (the) odds are against (something)
  • the odds are against something/somebody doing something
  • as a pig loves marjoram
  • at worst