Loss

Loss was an emotion. Sarah Jane Smith once said that pain and loss defined a person as much as happiness or love. (TV: School Reunion)

Information from invalid sources
An Ice Warrior was asked by John Nathan-Turner to convey loss, as well as tragedy, heartbreak, anger and despair, for a scene in which he reacted to the destruction of the rest of his squad of warriors. On the first take, his face did not move. (NOTVALID: Doctor Who? 149)