The refractory state (chapter 11) lasts ~20 minutes. Wait to react until it passes. Sure: type the scathing message during your agitated state and save it for later review, reflection, or consult with a trusted confidant. Once you hit “send,” you can’t unring the bell.
Inversely, when someone else is in a refractory state, understand they can’t take in new information (even an apology) until it has passed.