The smallpox episode has a number of serious issues, even assuming you allow for issues like time-course problems, the fact that the hospital is not anywhere near equipped for that kind of quarantine (and the measures shown are laughable), etc:
1) How did the Dad get the disease? They identified it as a strain of pox that was transmitted from rats to humans through bites, explaining how the slaves were able to be infected while the crew were safe. The daughter got infected by rubbing diseased scabs into a gaping cut (not sure how that would work, but anyway)--how did the father get it? If human to human transmission was possible, the above-deck crew would have gotten sick.
