The reanimated Patrick proceeds to devour multiple people in his cell block, turning them into walkers as well. The walkers at the fences have multiplied after someone is revealed to have been feeding them rats. The walkers inside the prison proliferate as the inhabitants evacuate the primary cell block, although the walkers, including Patrick, are quickly killed by the rest of the survivors. Carol takes care of a man, Ryan Samuels, whose daughters are Lizzie and Mika, and he realizes he has been bitten in the arm and neck. Ryan, coming to terms with his imminent death, asks Carol to take care of his girls, while Carol decides to bring them to him to say goodbye. She comforts the girls and encourages them to stay strong. Rick and Daryl discover that Patrick has been killed by an aggressive flu strain that causes the infected person to hemorrhage and choke on his own blood. The survivors decide to quarantine those who might be infected to prevent the virus from spreading. The outer fence of the prison is about to give way to the walkers, and the group tries to hold off the undead, discovering the rats in the process. Rick drives out the walkers by reluctantly feeding them his pigs, which are deemed to be possible hosts for the new virus. As Rick scraps his pig pen, Carl discloses to his father that Carol has been teaching the children how to use weapons. Rick gives Carl back his gun, disappointed that his attempt to live a quiet life has failed. Tyreese visits his girlfriend, Karen, who had been infected; later, he is horrified when he discovers two burnt bodies, one of them Karen's, and the other their friend David (who had also fallen ill).