Send Nest Video feed to device for 20 seconds

I want to stream a live feed of my nest doorbell to Nest Hub Max.
I want to do it for only 20 seconds or so.

Does anyone know how to set this up?
I currently have everything through the Nest Integration (I have a starling hub on the way).

can this be done without the starling hub?

So I am trying this, but it is just giving me a blank black screen.

Giving this a bump