General Provisions
The right of private defence of the body extends to voluntarily causing death (or other harm) to the assailant, if the offence provoking the defence is: an assault reasonably threatening death or grievous hurt; an assault intending rape, unnatural lust, kidnapping/abduction, or wrongful confinement (in circumstances suggesting no recourse to authorities); or throwing/administering acid reasonably threatening grievous hurt.
This lists the specific serious threats - genuine threat to life, grievous injury, rape, kidnapping, or acid attacks - for which the law allows even lethal force in self-defence, reflecting the gravity of these particular threats.
This is why someone defending against an attack that reasonably appears to threaten their life, or against an ongoing acid attack, may lawfully use even lethal force in response, under this section's specifically enumerated serious-threat categories.