The attached experiment shows you how to integrate Medialab with Qualtrics. Basically, you embed an iframe into the HTML. Just swap out my URL in for yours.
In order to prevent users from continuing the experiment without finishing the survey, I've used a custom item with password validation - parameter (xpassword). Thank you to user sgotovac for the javascript code for the password validation in my HTML files.
The Qualtrics survey can automatically log the subject number in embedded data in case you want to link MediaLab data to Qualtrics data - it makes it much easier for data analysis. Look at the HTML file for how to pass in the subject and condition variables. You'll need to know how to embed data on the Qualtrics end. It's easy! Just set an embedded data variable to pull in the value from the URL.
You can configure your experiment in any way - any number of URLs or MediaLab intermissions. This is just one example.