People like that don't need a reason apart from "because I can". They have a nightmare and try to make it happen.

...no-one is finally dead until the ripples they cause in the world die away... The span of someone's life, they say, is only the core of their actual existence.

Tʜᴇʀᴇ's ɴᴏ ᴊᴜsᴛɪᴄᴇ, ᴛʜᴇʀᴇ's ᴊᴜsᴛ ᴍᴇ. —Death

Night poured over the desert. It came suddenly, in purple. In the clear air, the stars drilled down out of the sky, reminding any thoughtful watcher that it is in the deserts and high places that religions are generated. When men see nothing but bottomless infinity over their heads they have always had a driving and desperate urge to find someone to put in the way.

Granddad was superstitious about books. He thought that if you had enough of them around, education leaked out, like radioactivity.

I dare say that quite a few people have contemplated death for reasons that much later seemed to them to be quite minor.

The author can always delve into his own personality and find aspects of himself with which he can dress his characters.