The Dawn Is Your Enemy

https://creepypasta.fandom.com/wiki/The_Dawn_Is_Your_Enemy
Trying to look up background info on the bump, so I guess I will polish it later.
You guys all know that Adult Swim sign-off bumper "THE DAWN IS YOUR ENEMY"? There's a reason they don't show it anymore. The last day the bump was used as a sign-off, instead of a normal running time of (estimated) nine seconds, it ran for an extended period of time until the automated services were overtaken by manual operation.
We all know the sound that shook our childhoods (or teen years). The resonating metal, the rumbles, the sound of metal scraping against metal. Feel free to look it up if you're a bit rusty.
Now, when the audio cut, it doesn't sound complete, it's not finished, not over. The producers of AS/CN were purposely cutting off the rest of the sound, and for good reason. The rest that followed was the exact reason why you'll never see this bumper again on the air.
Once again, it's supposedly only run for about nine seconds, and this is a rough transcript of the usual audio: Resonating metal, followed by a rumble, followed by scraping metal, and other rumble. End bumper. So what could you put together with that? Nothing rings a bell, right? Exactly.
This part that they used is utilized effectively to scare off children that have still tuned in to Adult Swim. It even gives adults goose bumps because it's that good. It's closely rivaled with the hammer clinks in the "William Street" production card in nightmare fuel.
Getting back on topic, usually a Cartoon Network employee would enter the control room left by an Adult Swim crew member and take over for a day. It wasn't quite the case that day, however. The usual man schedule to cue the sign-on and such programming for CN for some reason did not start up the day schedule. No one knows if he did this purposely, and whether or not his contract was terminated. This was the least of problems CN had at the time. What followed the common nine-seconds was an extended two-minute broadcast of some of the most horrifying audio ever heard on public television.
The metal continued to resonate, and the scraping continued. Slowly, an uncontrollable sobbing came clearer. Not one person was crying, but a multitude of people were screaming and yelling.
As the metal scraped, the screaming grew louder. Soon, you could hear the slicing of flesh, the grinding of bones, the gushing of blood, and the guttural death rattles of people dying. 
All across the United States, millions of children and adults were being exposed to what sounded like a barbaric mass murder. People were calling in all across the country, crying or screaming or begging for it to be turned off. Something kept their eyes attached to the screen and kept them listening to the broadcast.
People assume the control room was finally gotten into, and the bump was shut down, ending a traumatic experience no one could undoubtedly forget. In the last few moments as the resonating metal grew into an unbearable volume, the channel showed the peeking sun winking at the viewer, and the channel cut to Bars and Tones.
How was Cartoon Network going to cover this up? No one knows their exact tactic to this day. Multiple theories have been thought of, ranging from a pre-emptive "cease and desist" to possible news articles to subliminal viewer hypnosis over the following weeks.
While all public evidence does not officially exist, Cartoon Network officials do acknowledge a hijacking of the channel's frequency on the day but go into no further detail. All late morning bumps, including TDIYE, were replaced with the corresponding ones from the 1:30 AM timeslot. Word is, however, that somewhere hidden in an onion site (accessible only via Tor) is a recording of the bump played that morning.
The question asked the most among the few who remember this is how Cartoon Network got the audio in the first place.