Trying to direct a non-theme driven script.

Basically I have a script I wanted to direct, but I find it difficult to do so, cause their is no theme to really drive the story. Basically two people are put in peril by a villain, and they have to get out of it, and that's it. But the characters do not really go through any changes and learn any moral or life lessons or anything. They are still the same people in the end, and it feels like a themeless story. Not that that's necessarily bad.

Alien and Halloween for example, don't really have philosophical themes that get the audience thinking about some sort of deep debate in the end. They are just stories that are told for thrills and chills and that's it. But for some reason I finding it hard to direct a story like that, like having no theme, is giving me director's block, if that makes sense. Does anyone have any input on something like this perhaps?