You can't do that, it's frustrating absolutely, but look at it from another perspective. Brandon Staley did an amazing job and finally received an opportunity and rose to the occasion and is now a Head Coach in the NFL, that is the way it is supposed to work and I will never understand how some assistants don't get opportunities, but everyone should have the right to improve their standard of living and move freely to do so.
It's already set that teams do not have to grant permission for a position coach to be interviewed for a Coordinator, the good teams allow it, but some don't and hopefully Staley won't try to take some of the Ram assistants with him, like Rams defensive line coach Eric Henderson as DC for example.
Let's not forget how the Rams got Staley, they asked the Broncos permission to interview him as he was the Outside Linebackers Coach and the Broncos could have denied permission, but they didn't so now, we shall see what lies on the horizon and although I'm upset too, I still believe that assistants should be given theses opportunties.