[A lot of Sakamoto's friends had died during the war because medical treatment in that time, before the Amanto's technology had been integrated with that of Earth, was incredibly primitive. You were more likely to die from an injury than from direct contact with an Amanto, and that death took a longer time and was more painful. Infections. Sakamoto had seen them. He wasn't afraid of dying, wasn't afraid of the Amanto, but... Doctors always made him uncomfortable. Sure, they were more reliable now, but he never wanted to be in bad enough shape to have to see one.]
They think livers exist, ahaha! I wouldn't be alive if livers existed!