“stand down” is a government thing, possibly a military thing too.
Whenever something weird or bad happens, there is the potential for a “stand down” whereby people are to stop doing their jobs for a few minutes and reflect on the event that occurred.
We had a fatality in a power plant several years ago, and as a result, TVA went into a company-wide “stand down” where work was to stop so that we could think about and honor the person that had died.
Never heard of it in the private sector - yeah, we’d get the information and would feel remorse, but we never shut down work production for such an event. Granted, people that knew the victim would take half a day to visit the funeral without any repercussions, but no “stand down”.
Never heard it used like that. I thought stand down meant relax from an alert security posture, in other words stand back, step off. The opposite of standing down a unit is standing up one. But then I don’t know all the inside baseball.