John Ellis

John Ellis was a citizen from 1953 who accidentally, with Diane Holmes and Emma-Louise Cowell came through the Cardiff rift.

Biography
John saw his son in the future, who had Alzheimer's disease. He saw no purpose in his life now that his family was gone.

He tried to commit suicide but Jack Harkness stopped him. After explaining himself, Jack decided to let him kill himself. He did so by carbon monoxide poisoning. (TW: Out of Time)