I had a teacher once who said to add conflict, give characters a countdown/ clock . 

So here's the thing:  Your characters have a problem to solve- but they have a limited amount of time to do it.  For example, by midnight, by daybreak,  within an hour, etc.  

Write a scene of part of this.  You can show the planning, the climax. or how they're dealing with the gradually decreasing time. Are they starting to panic or calm?