The current version does not include error handling for missing files.
However if you leave a blank trigger value in the dynamic plugin, it will use that one if none of the other trigger values are found as the default, so that may work in your case.
What is the situation where the file doesn't exist? How are you setting it up so that this is a common error you need to account for? Maybe we need to add a feature to better account for this, so I'm interested in what you are looking for.
You may be able to simply delete the die(); statement causing the code to stop running and then your server 404 page would be displayed. Perhaps that is the only change we need to make. I'd like a better description of why and where you run into a page not found issue so I can give the proper advice on addressing it.