If you think you're going to die within the next 24 hours, then go to the freaking ER. This isn't rocket science. Heck, if you think you're going to die within the next 24 hours, you shouldn't even bother with the primary care doctor at all and just straight to the ER.
Yet you think my example means the people thought they were going to die.
If you're so bad off that you're going to die within 24 hours, then you would know it. You would be extremely sick, not just sick.
The things that kill you instantly with no warning are things like heart attacks and strokes. Those aren't thing you make appointments for.
Yes, you can die from non-emergencies, but it's not going to happen overnight. Those are more gradual deaths. That's my entire point.