When preparing those that had been bitten to be put down Blake says that they are going to use ampules of morphine (the kind used by combat medics) to put them to sleep first. However the box of ampules, as well as the ampules themselves, Blake and Alicia both use are labeled as being doxycycline, not morphine. Doxycycline is not even an opioid analgesic, it is a tetracycline-based, broad-spectrum antibiotic.