The characters of Geoffrey Bennett and Douglas Taylor are shown as having served together in WWII. Unlike the United States Air Force, the Royal Air Force was integrated during the war, with thousands from the Caribbean colonies volunteering to fight against Germany.
At the end of the episode, Doctor Michael Evans suspects three substances that could have caused warts and cancer in patients, namely lead, tin and asbestos. Doctors later discovered that both substances have different levels of toxicity for human beings, with asbestos being the true cause of these evils, culminating finally in the death of the patients.