The Aeon's End rules say, that if you focus one of your breaches, you may prep a spell onto that breach. Are you also allowed to do that outside of your own main phase?
For example an ally might focus one of your breaches. Can you immediatly prep a spell onto that breach? Or if you cast Jagged Lightning in your casting phase and choose to focus one of your breaches, does this allow you to prep one of your spells and even cast it in the same casting phase?