The cult doesn't believe in 'natural' death.
"murder is death, death is murder"
when their time comes they are notified so they have time to prepare - after the prep period is over a fellow cultist wacks 'em on the forehead with the knob on the end of a kill stick.
There was some QR post on this in 2018, giving details about the ceremony, the sacred wacking stick etc. The poster asserted that the UK's beloved 'Queen mum" had her head bashed in this way.
A full literary account of the death gnostic protocol can be found in the Avignon Quartet .
>A letter informs the Egyptian Sebastian Affad that he will die; a mix up has caused major ructions within the Gnostic sect in Egypt. Affad is called back to Egypt for admonishment. Before leaving Switzerland, however, he has asked Constance to use her psychiatric skills to treat his son, who has become autistic. She is gradually successful in working with the boy. After Affad returns to Switzerland from Egypt, the couple renew their relationship.
>The psychopath Mnemidis intervenes. After escaping from the institution where Constance works, he goes to her flat, intending to kill her, but murders Affad instead. The book finishes in a surreal manner. Affad seems virtually to disappear from Constance's memory; and two chapters give conflicting accounts of Constance's action upon the death of her boss Schwartz. Unexpectedly Sylvie reappears, for the first time since Monsieur. (She is said to be a fictional creation of author Aubrey Blanford, also introduced in the first novel as a character). She begins an affair with Constance.
https://en.wikipedia.org/wiki/Sebastian_(Durrell_novel)