The boys think they've got the infection, and they decide to test their hands for it. They're worried that the finger they cut off isn't growing back, but yoshioka reassures them that it's fine. He also reassures the girls that they won't have to take any antibiotics to treat the infection. He tells them that he'll get a sample of the infected's blood and then perform a "viral culture" on it. He'll then be able to tell whether or not the infection is M or F. The boys are worried that they'll have to use a drill to kill the infected. Aww, forgive me, maeda, kun . What is that drill for? It's coated in blood, and the only thing that can cure it is to kill both the M and F-viruses. They decide to go ahead and kill the M-Virus first, and then kill the F-Virus.