Styre experimented on one of his prisoners, testing the life survival of a human without water.
By the time Harry Sullivan found him, the prisoner had been shackled to a rock alcove for nine days, desperately thirsty. Though Harry wet a handkerchief and let the dying man suck out the water, the man was too far gone to save and slipped away while he was off tending to other matters. When Harry returned and found him lifeless, he checked for a pulse. Realising how Styre had cruelly tortured him, he lividly called the Sontaran a "murdering swine".
Styre noted he died in nine days, seven hours from the moment the experiment began. The man suffered impairment of mental faculties, motor reflexes and physical coordination after only three days. This allowed him to concluded that humans could not survive without fluids for very long, while at the same time could be asphyxiated in them, following the results of his prior experiment, drowning a human. (TV: The Sontaran Experiment)