Thanks for posting to PX Community!
It is not currently possible to embed a PX Survey directly within a PX Engagement. Please post this as a PX Product Idea, since that would be a nice option to have available.
Within a PX Email (or any Engagement), you can include a custom “button” or “hyperlink” that when clicked will redirect users to a specific PX-tracked page within your application. Then, you can use specific Audience Logic for “URL” or “Query Parameters” within a separate PX Engagement to trigger it to play for the user when they land on that page inside your PX-tracked application.
Much of this configuration is covered in this previous PX Community post.
I hope this helps!