So what exactly does this mean to you? I'm trying to figure out why someone in the background saying this is being used by you as evidence the federal government set up a fake massacre. ...
I'm not offering it as evidence of "the federal government['s]" direct involvement, nor am I suggesting it's an indication that the massacre didn't happen.
...Are you thinking someone in the local police department's dispatch center heard some information that the feds had set up a fake massacre? ...
No, I think it's a possible indication of confusion due to an ongoing active shooter drill.
Confusion-fomenting drills coinciding with real life events have become very troubling staples in national tragedies since 9/11.
Would you think it possible that is a reasonable rumor to happen despite it being real?
I think it's far more likely that the rumor had its basis in a drill that took place concurrently with the shootings at Sandy Hook Elementary.
There's a small body of evidence beyond the 911 audio that supports this possibility.