i like that game, but i always end up focusing on building huge prisons. that's a great way to level your doctor, by performing all kinds of procedures on your prisoners. i suggest starting off by replacing their legs with wooden peg legs for the speed debuff in case they escape. you can also remove a kidney and a lung from each prisoner and i'm pretty sure that also weakens them if they escape. you can swap organs around between prisoners too, and that'll help level your doctor.
and if you decide to recruit prisoners into your society then have your doctor replace their peg legs with bionic legs, which give them a speed buff over even regular legs. also give your doctor an intern who can eventually upgrade your doctor with bionic eyes and arms which makes him an even better doctor. and if you give your doctor bionic legs then he becomes like a super fast EMS and rescues everyone by himself. pretty soon it'll be hard for anyone to die with such a badass around. but be sure to have pretty nice surroundings and comfortable a spacious rooms for workers because living next door to an organ farm/prison run by an evil cybernetic doctor bums everyone out.
edit: oh yeah, and always keep pyromaniacs in jail. do not let them out. in fact, harvest their heart or liver in case an important peon needs one in the future. whatever you do don't let pyromaniacs into your village.
(Edited 6 minutes later.)