Rabbits!

"Rabbits!" was an negative exclamation favoured by Tegan Jovanka. She used it to indicate displeasure or frustration at an event. (PROSE: Graham Dilley Saves the World and elsewhere)

Behind the scenes
The exclamation does not seem to particularly be popular, real world slang. It may have simply been a Janet Fielding-ism. However, Australians do call inept cricketing batsmen "rabbits". Since Tegan is established to be au fait with cricket in Black Orchid and in later stories like The Forgotten and Graham Dilley Saves the World.