Pex

Pex lived in the Paradise Towers, and claimed to be a great hero. In actuality, he was an "inbetweener" who had stowed away on a shuttle headed to Paradise Towers in order to avoid fighting in a war. Ashamed of his actions, he took to patrolling the corridors of Paradise Towers. He sacrificed himself to kill Kroagnon. But later, as the TARDIS dematerialized, the sign 'PEX LIVES' appears behind it. (DW: Paradise Towers)