URGENCY
matter of life and death
a matter of great urgency; an issue that will decide between living and dying. (Often an exaggeration. Fixed order.)We must find a doctor. It's a matter of life and death.I must have some water. It's a matter of life and death.
not able to wait
to have to go to the bathroom urgently. (Informal.)Mom, I can't wait.Driver, stop the bus! My little boy can't wait.