The shooting in Scotland that Seamus refers to is the Dunblane Massacre, a shooting at a Scottish primary school. It is the deadliest shooting in British history and led to the outlaw of many gun ownerships. British tennis player Andy Murray was a pupil of the school at the time.
During the scene were the bagpipes are playing in the ambulance bay, Owen states that he thinks the sound of bagpipes are "beautiful." Kevin McKidd, who plays Dr. Hunt, is Scottish.