The Spanish Flu

It’s 1918 and the Spanish Flu rages. More of our young soldiers are dying in sickbeds than in the trenches in Europe. You just received a telegram from your neighbor, a mysterious reclusive doctor. He writes he has been working on a Spanish Flu vaccine in Washington DC and just confirmed batch # 7 works. A batch is in his lab and he asks you to deliver it to a doctor who is waiting at the train station to inoculate a group of local boys who are leaving for boot camp in an hour. There’s a problem! The doctor’s assistant uses a strange security system to keep his boss’s work safe and he can’t be reached. Can you figure out the security system and deliver the vaccine in time?