The default behaviour when using the "Page" command is to use the Desk Number from the users profile - instead of Dynamic DID.
So the person being paged receives the Vocera users desk number as a call back number. If the person calls the number as sent they go to the Vocera users desk phone... which usually not where they are when they page.... otherwise they would have just paged them directly from the phone.
For the person that received the page to get back to the Vocera user, they have to dial the genie number and then the desk number to get back to the badge of the Vocera user.

We have had to set up all of our users desk phone info in the home phone field so they can take advantage of our Dynamic DID configuration when they are out on floor.

When they want to forward calls to their desk they have to use the command - "Forward my calls to my home phone"