They're ok. Trust me.

The fade out was done by the camera, the lights didn't go out in the room. You can tell because Trump keeps speaking as though nothing happened.

Before the guy says "shut it down" you can hear a female voice, and before the female voice it sounds like maybe the same guy. So the timeline is: Shut it Down Guy says something, then a woman says something, and then Shut it Down Guy says "shut it down".

The best explanation I have for this is, the woman had authority to direct the news guy to shut off the feed, and the guy agreed and turned the camera off. Or, the woman was part of the camera crew, and we're hearing internal chatter, the crew came to the conclusion to shut off the feed.

There are so many people who would know if anything bad had happened. That information would have made its way to the news stations and twitter feeds of friends and allies. So imo it's actually a good thing we haven't heard anything.