Write a story in which time is running out. Let the ticking clock be the impetus, not the focus, for why your characters feel the way they do. Let your reader understand the stakes involved because your characters show how they feel emotionally through their actions. Let the story lead up to the moment that time runs out – whether you go on to show the aftermath is up to you, but use the countdown to zero to move the story along and then give your reader a payoff. Give this exercise fifteen minutes of your time – in fact, set a stopwatch and let the countdown spur you forward in your writing!
Write it up and see what happens.