Huge Venom Load: The amount of venom injected into the body by a king cobra is much higher than that of other snakes in a single bite. A king cobra can deliver enough venom to kill an elephant in a single bite.
Neurotoxic Venom: The king cobra’s venom affects the nervous system. This rapidly paralyzes the respiratory muscles and leads to suffocation. Every minute that treatment is delayed increases the risk of death.
https://youtu.be/4sL7pvWIkiQ
Lack of availability of medicine: King cobra venom requires a specific anti-venom (Monovalent Anti-venom). The polyvalent anti-venom, which is commonly used for snakebites in India, is not effective against king cobra venom. Specific medicine for king cobras is not available in all hospitals in India (it is mainly imported from countries like Thailand).
Blood pressure drops rapidly: As the venom spreads through the body, the heart rate slows and blood pressure drops dramatically. This can quickly lead to shock.
Large doses required: A king cobra bite requires more than ten times the amount of anti-venom given to a normal snakebite victim. Getting such a large amount of medicine quickly is often a challenge.
https://youtu.be/4sL7pvWIkiQ