You know the saying "You cannot control what people do, but you can control, how you react".

How do you control how to react when you are under emotional distress?

From Eckhart Tolle I know that the only thing you can do is observe.

But in moments of pressure, of stress, I do not have time to observe. I need support from my body. Not some fucked up memory of the past in which I did not succeed in a similar situation.

Also, in my experience, you cannot "observe in advance" to then have stillness of mind when it matters.