Stall was not happy from the beginning, the only friend he really had was his boa constrictor and his alcohol. In the beginning, with the mentioning of one of his friends dying and the other one amputated, brings about his drinking addiction and opened up how he was depressed. He knew he could not enjoy the good times he had with his friends before the robots got the best of them. Yoshimi changed all of that, he may have still been drinking and wrestling with his boa constrictor, but he was happily in love with her and loved everything about her. After seeing what 8A8 did to her, that was his last straw, a moment of post traumatic stress, seeing his friends suffer the same fate. His suicide was a sense of giving up, he could no longer take the deaths of those who meant so much to him and the endless war of fighting robots. It just became too repetitive for him to handle. He could not bear growing a connection with those he train and only end up having to see them die or be brutally injured. He killed himself through death by his own pet snake, who he enjoyed playing with so much, he chose it as the way ending his terrible