Twist is opposite of expectation, or rather the enemy. Twists are used to break the expectation, then come up with even more fearsome result. Rather that would be jumpscare with delay of tempo or a calm yet creepy scene that resets the anticipation meter, it serves as a powerful weapon.
For example, in the movie "Silence of the Lambs,"
the director Jonathan Demme uses crazy patients to make the audience expect Hannibal Lecter as a very freaky being, yet he makes a twist and brings him up
to be a calm psychopath.