You'll see a lot of "different" things on the New York City subway; some of it good, some of it downright atrocious. Bettina Banayan's actions fall into the former category.
Banayan, a Manhattan resident and student at the French Culinary Institute in New York City, elected to film herself frosting a cake while aboard the train. She clearly has no problem working under pressure and in tight spaces.
People have found far less aesthetically-pleasing things to do on the train, so Banayan deserves extra credit for her accomplishment, and because she shared her creation with fellow passengers. Talk about being in the right place at the right time.