I always thought of it as shutdown rather than meltdown.
Like Felinity mentioned - 'Flight, Fight or Freeze' - Freezing would be a loss of cognitive abilities under acute anxiety or stress. Like 'playing dead' until the danger passes.
Quote:
Our body's natural alarm system (the fight-flight-freeze response) can be activated when there is a real danger, such as coming across a bear when hiking in the woods. In this case, you may flee (e.g., run away from the bear), freeze (e.g., stay still until the bear passes), or fight (e.g., yell and wave your arms to appear big and scary).
But this response can also happen when something simply feels dangerous, but really isn't, such as being interviewed for a job. For example, you may feel jittery, on edge, or uncomfortable. You may snap at people (fight) or have a hard time thinking clearly (freeze). These feelings can become overwhelming enough that make you want to avoid doing the interview (flight). Many people stop doing things or going places that make them feel anxious.
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For time has imprisoned us,
In the order of our years,
In the discipline of our ways,
And in the passing of momentary stillness.
We can see our chaos in motion.