You basically want to suppress the master template.
What I did for LORSM where we want to display an assessment without the site template, is to make all the pages I want to use an include, then include them in LORSM without the master tag and use them within assessment with a master tag.
I imagine there might be a way to create an include tag that somehow supresses the master tag, if the included page has one.
This would very easily solve the problem, but I couldn't figure out how to do it yet.