The bearded Muslim constantly wears headphones and clicks prayer-beads while reciting lines from the Koran as he walks in a tight loop.
His eyes seem devoid of life – and he is clearly mentally disturbed.
His guards have dubbed him The Pacer because he never varies his step as he prowls the same stretch of bare concrete floor all day, every day.
Two fellow inmates enter the large communal area where he trudges.
But they completely ignore The Pacer and instead switch on a flat-screen TV mounted high above them on the wall.
The pair – both shaven-headed but with long beards – chat away as they flick through the channels.
But I can't hear them because I'm on the other side of a two-way mirror in one of the network of detention centres for alleged terrorists at Guantanamo Bay in Cuba.