Help with setting a value in an intent script

I’ve been fighting this one for a while, so hopefully someone can help point me in the right direction.
I’ve setup Snips to pass a location in one of the slots. If there is no location specified, I would like to set the empty Slot value depending on the Site_ID.
Below is my intent script, and it all works except the tv_location that I’m setting doesn’t get passed to the action. It’s set correctly in the speech section. I can repeat the same script in the action section, but I was hoping there was a better way.

    type: plain
    text: >
      {% if tv_location == null %}
         {% if site_id == "default" %}
            {% set tv_location = "living room" %}
         {% elif site_id == "aiy_kit2" %}
            {% set tv_location = "guest room" %}
         {% else %}
            {% set tv_location = "unknown" %}
         {% endif %}
      {% endif %}

      Turning on {{tv_location}}
  - service: media_player.turn_on
      entity_id: 'media_player.{{tv_location | replace(" ","_")}}_tv'