"Nastasha Romanenko: What awaited Snake after his brief encounter with Liquid was Ocelot's KGB-tested 'interrogation' techniques. Ocelot apparently had no interest in extracting information, but rather appeared to be enjoying the acts of torture for their own sake. Snake's ragged gasps echoed from the radio in the silence of the control room. The heart rate and other physiological data transmitted by his nanomachines graphically demonstrated the extent of his suffering."
January 1, 1970
https://en.wikiquote.org/wiki/Nanotechnology