How long does it take to die?

Direct contact with the front of a train moving at 50MPH or greater. It’s also very messy.
Hiroshima, Nagasaki.
Spirit Lake residents who refused to evacuate were vaporized along with the lake when Mt. St. Helens erupted.
Being struck by lightning though some have survived.
Just to name a few.

Euthanasia solutions used in veterinary medicine are very nearly instantaneous when used intravenously.

Accidents. Broken neck. Decapitation. Explosive decompression. Projectile penetration of the brain. Impact at high speed against an immobile surface. Severed spine.

Clinical death is always instant. You are dead when your brain is dead so there is no middle ground you are either deat or alive.

your entire life

Depends on how you want to pull the plug…...Your question scares me!

Life is slow death, but speeding it up is no problem.

ummmm…. wh do you ask? But it depends on what you have, it took my grandma about a month and my grandpa a couple of days.