Suspense

Suspense is the element that authors use to try to leave the reader hanging, trying to figure out what will happen next, especially when the author does this at the end of the book without actually telling what happens. This leaves a particularly strong effect.

Suspense is a feeling of uncertainty and anxiety about the outcome of certain actions, most often referring to an audience's perceptions in a dramatic work. Suspense is not exclusive to fiction, though. Suspense may operate in any situation where there is a lead-up to a big event or dramatic moment, with tension being a primary emotion felt as part of the situation.

For example:

In this shot the suspense is not knowing the outcome of this showdown, will the hero die, or will the hero overcome his enemy, this leaves the audience watching and concerned for what’s going to happen

In this shot the suspense is the unknown of what’s upstairs, not knowing if horror awaits or someone is going to come down threatening the mood of the characters, this leaves the audience scared and on edge about the following scene