there isn't a name for it.
The closest I could come up with would be Odynophobia - Fear of pain, or Thanatophobia - Fear of death. However, I wouldn't consider fearing being tortured to death necessarily a phobia, I would call it common sense.
Necrophobia.
Necrophobia is the name for the fear of death adders.
the name for the fear of death is called thantophobia .
pyrophobia
Necrophobia Phobia name for the fear of death. It is a common phobia
premuertophobia
'Flogging a horse to death' means being obsessed with something. It is not a phobia.
The fear of death is common. Elevating it to a phobia is not.
Everyone is afraid of dying, but an extreme fear of death is necrophobia
The irrational fear is called a phobia; the experience or object that triggers a phobia could be called a phobic experience or object.
They have been around since the first sentient beings, all sentient beings have fears. Although, they weren't known as "Phobia's" until the late greek period, all phobia names are greek as "Phobia" is greek for fear and the beginning word (Eg necro for fear of death) is greek for whatever the fear is of (so "Necro" means death in Greek)