ember: detect item removal from subroute controller /rentals/grand-old-mansion

i'm using ember with a nested route like shown in this example: http://ift.tt/2e4jG2o

i've implemented a WebSocket adapter and now i wonder:

how to know when the actively viewd item was deleted?

1. say you visited this link:

   http://localhost:4200/rentals/grand-old-mansion

2. and then the 'grand-old-mansion' got deleted.
   how to know that?

@locks on slack recommended to use Ember.Evented with trigger from an ember service which i can't get working.

anyone having a recommendation on the issue?