In the third season, Barrie's character of Liz as well as Barney's children were occasionally mentioned but never seen. In the spring of 1978, Barrie returned to the series as a guest star reprising her role of Liz Miller in the episode “Quo Vadis”. In that installment Barney gets shot on duty but survives his attack virtually unharmed. However, Liz, upset by the incident and unable to stand the pressures of being a policeman's wife, gives Barney an ultimatum – to either give up his police job so they can move to a safer neighborhood or end their marriage. At the end of the episode, Barney and Liz separate.