The danger zone of high blood pressure is between 180/120 and if the blood pressure gets to 180/120 or even higher you need to call 911 and seek immediate medical help as that high of blood pressure puts you at risk of death from stroke, heart attacks etc.
Call 911 immediately if your blood pressure reaches 180/120 or higher or if you're not feeling good at even a lower blood pressure call 911 and get someone there to help.
It's better to be safe than sorry.