Injects are events in the scenario. In the jargon of interactive narratives we might call these "beats".
In the case of crisis simulations, they're called "injects" because the intention is to inject some tension into the exercise and require participants to react.

Creating Injects

Injects are created by
  1. selecting the Facilitator channel on the content item
  2. adding an Inject block to the bottom of the content.
All content for the facilitator channel is sent to the exercise control feed ("excon" for short). 
The illustration below shows content from the scenario editor and how it appears in the facilitator dashboard

With the content item selected, click the + that's shown beneath it. This will add an Inject. 
If the channel is set to something other than facilitator then "multichan" will be displayed

Content connected to the Inject block is what's published to the participants.
Note that it doesn't matter what persona you use for the facilitator channel but  you might prefer to create a persona called Facilitator as shown below in stage6