the spine is the longest (continuously) running of the bots currently active, and given his activation time he was around when the bombs fell. the walters probably powered down rabbit and hatchy early enough, but since the spine's newer, and a little more durable, they probably waited on him. but too long, and while they were shipping everyone out towards a vault, they got scattered. and he found a family to help and he stayed as long as he could but he watched the world burn, and people he cared for die terribly and to be alone in the desert wandering for two hundred years

cause you can bet that peace programming code snapped a long time ago, he's probably afraid of loud noises and can't stay around bodies too long, and you know for sure he tries not to hurt anyone because everyone's got it rough but sometimes that old bot cant help it and

after so long searching he found his brother and sister again but they don't have any idea what's happening, or that they know each other, and he has to keep that up the entire time he's with them, cause they haven't got a clue, they were powered down for so long

just