In the key scene, journalist Glenn Greenwald visits Snowden at a hotel room in Moscow. Fearing they are being taped, Greenwald communicates with Snowden via pen and paper.

While some of the exchanges are blurred for the camera, it becomes clear that Greenwald wants to convey that another government whistleblower — higher in rank than Snowden — has come forward.

The revelation clearly shocks Snowden, whose mouth drops open when he reads the details of the informant’s leak.

Also revealed by Greenwald is the fact that 1.2 million Americans are currently on a government watch-list. Among them is Poitras herself.