From Merriam-Webster's 11th Edition: :a sudden or unexpected reversal of circumstance or situation especially in a literary work.
One of the best things a suspense novelist (or any novelist for that matter) can do is give their reader a surprise or two. Surprises keep interest up and the reading stays fun.
But throwing curves can boomerang if not handled well. Any sudden flips you create have to be plausible, and work for the story.
As a reader, there's nothing more frustrating than feeling like you've been relegated to an outsider position (within the pages of your very "own" novel) because you don't understand what just happened, and you're pretty sure you never will.
Brainstorm peripeteia options. Pick the best of the worst. The one that throws the biggest curve, creates the most surprise or delight. But make sure it could actually happen. Fictionally, that is.
It's all better with friends.