[moduspol]

It's also a rocket launch, which is commonly accompanied by a countdown.

It was also pretty common to have that countdown broadcast over the radio, as many people would show up just to watch the rocket launch. Even without a radio broadcast, it'd be as simple as a walkie talkie inside the control room and another with the filming team.

This shows up on the internet every few months, and I'm still astounded by how much attention it gets. It is not nearly as remarkable as portrayed.