Every story needs dramatic tension — a sense of mystery -- to create "What Happens Next?" This makes the reader want to turn the page. Understanding the difference between inner dramatic tension, which is character-driven, and outer dramatic tension, which is plot-driven, helps you to deepen the plot of your scene.
The scene in the picture above has a built-in tension for your thriller. Whose point of view do you use to propel the scene?
The kidnapper or the little girl?
What if the adult isn't a kidnapper? What is he doing, and why?
Does the little girl know the adult?
Is the adult in danger of being found out? Is the hero of your thriller on the other side of a closed door?
The tension comes not only from the act portrayed but also from the feelings and thoughts of the point of view character. Both inner and outer dramatic tension are called for!
These three pictures below are excellent examples of the difference between inner and outer dramatic tension.