If you don't think about it, it won't happen.
It was child's logic, but Karkaroff used it anyway – unconsciously, in desperation. He knew he was doomed from the night he fled, knew his pursuers would be stopped by nothing, but he refused to outright believe in his death. Even when they were mere days behind him, he contacted no one and penned no will, clinging instead to shards of what passed for hope. If he ran far enough...if he hid well enough...if he believed hard enough...he would be safe.
It was child's logic, and it ended him.