This week: It's the show's last Halloween episode as Gates is a real jerk to Sam, Banfield remains her usual curmudgeonly self, a bird gets loose in the ER, Brenner takes issue with a mom's behavior after her son was in a fight at school and stabbed another student with a fork, Daria is acting very weird and flirty, Frank dresses up as Julius Cesar, Morris and Tracy make a great save, and Neela is thrilled when Ray makes a surprise visit to County General.