A Flight Attendant realized after arrival she had not armed a door because of distractions related to removing an ill passenger at departure time.

Narrative

Just after receiving pushback clearance; we received a call from the aft galley stating we had a sick passenger who ran to the bathroom. We cancelled the push and discovered the passenger had self-reported having the flu and being very ill. I made the decision to remove the Passenger and coordinated with customer service and Dispatch. After landing; mid galley Flight Attendant reported that when she went to disarm door; she realized she had never re-armed the door after passenger removal. Flight Attendant filling out report. According to all (including mother and daughter of passenger who was removed); the passenger was visibly 'not well' by all accounts. She never should have been allowed to board the airplane; particularly with all of the information available on influenza and public health risks. The distraction to the Flight Attendant caused by the return of the jetway and removal of the passenger caused a departure with door 2L unarmed. The increase in risk of not being able to get off the airplane in the event of an evacuation could have been avoided by a quick screening of the passengers boarding our airplanes.