Seymour and his twin, Jason, are both born inside Section to an Operative named "Lisa", who was later killed on a mission. As an experiment, one twin was released the other remained in Section. Walter decided who would go and who would stay – by the flip of a coin. Both twins show remarkable talents in the field of technology. As Level 4 Head of Communications, Birkoff has many responsibilities. Duties include Intel verification, system security, mission analysis, tactical liaison, etc. Birkoff is known to have performed as a field op in only two missions: infiltrated a terrorist organization in "Any Means Necessary" and posed as a courier in "Into The Looking Glass". In all other missions he performed as the on site Comm expert. Near the end of Season 4 Birkoff builds an Artificial Intelligence as a backup should he ever become "unavailable". The AI presumed to take over for Birkoff and in order to take down the AI, Birkoff "cancels" himself and the AI. Jason, his twin, is then "recruited" and brought in to take Seymour’s place. This is done so that the death of a department head would not show up on Ops’ record as an anomaly.