Frank and Dave go into one of the EVA pods under the pretense of checking its transmitter. Inside, where HAL can't hear them, they discuss whether HAL is malfunctioning. They decide to put the unit back and see if it fails. Poole says if HAL's wrong then they'll have to disconnect him. Bowman agrees, though he isn't sure what HAL will think about such a procedure.
Outside, HAL is reading Bowman and Poole's lips. Excuse us a sec while we go put our cell phone in the other room.