to kill the rancor: enable solo mode run in, go to the pile of bones, DO NOT ATTACK!, pick up grenades from pile of bones, throw one, run to door. Either rancor will follow and you can shoot and grenade it through the door, or if you reach the door and it does not follow you repeatedly go back in and throw 1 grenade then run to door. PHEAR ME 4 I AM REVEN REBORNfind the rakghoul serum :get strong enough so that your group can take on 4-5 rakghouls at a time.walk in the undercity, find the pit full of rakghouls, take them all on. if you survive there are 3 bodies there , one has the serum. either sell the serum or take it to the medical center and make more, or take it to the infected undercity people and cure them