Director Vince Gilligan describes a deleted scene from Breaking Bad's final episode in which Walter White, the former chemistry teacher-turned-methamphetamine synthesizer, runs into a former student. Dying of cancer, Walt asks the ex-student if he thought he was a good teacher. The young man replied that he was and that he remembered a demo of coloured flames. When Walter asked him what it all meant, the student replies “that chemicals sprayed through flames can make different colours” —perhaps only a chemistry teacher would let out a long sigh at this response.
Thanks to Enrico Uva, Laurenhill Academy, St. Laurent QC for bringing the deleted scene to our attention.