... Alternately you could actually programatically get the outline ID and/or menu item id - but I think this would be the wrong approach because you would be hardcoding variables into your TWIG code that are unique to your specific site and which may change.
This will help though if you do take the latter approach
http://docs.gantry.org/gantry5/advanced/creating-a-new-particle#pulling-gantry-configuration-data-using-twig
. Use the Gantry 5 debugbar to find the correct variable name.