You hear this a lot. Don't freak out. Don't panic. Don't blow this up any bigger than it is.
Part of what this advice is suggesting is: Don't get caught up in your emotions and the situation. If staying with your breathe can help you hang in there longer, stay focused and precise, then yes! Just breathe.
But don't confuse just breathe with
just back away slowly,
just go find a safe place to hide,
just protect yourself,
because that is bad advice and that is not what we are doing here.
Just let go of what you are stuck on.
Let go of having to control the situation.
Let go of 'this or that',
Let go of value judgements.
It's hot in here. It is going to get hotter.
You have to dance to the music that is playing.