Burial Chamber's farming

did 889 burial runs. Have droped 3 raw doctors and could buy 3 from the drops and lucky 6link jack carcasses. the first 2 doctors droped in ~100 burials , the last one on the run 889. all 3 cards droped on map with nemesis mode. i dont know if it drops only on nemesis maps or on any map... could be just a coinsidence. (sorry for my broken english)
last card droped from the sarcophag in the midle section and the first two from white mobs and the the last section of the map. I have 50iiq