The devil truly is in the details. When it comes to the delivery of information to students about the research conducted over the past several years on the modern fire environment by UL and NIST, every detail matters. As today’s fire instructors are incorporating information into their presentations gained from the experiments at Governor’s Island, Spartanburg, Milwaukee, and in the UL laboratory, they must take great care to be specific or the message will be lost. In some cases, the message may even do more harm than good. In a recent class I attended on fire tactics, the well-respected instructor showed a compelling video from the Spartanburg burns in which two bedrooms of similar size and layout are on fire on opposite ends of the second floor of a house. The firefighters in the video first direct a straight stream into the window of one bedroom from an exterior position, aiming at the ceiling and allowing very little nozzle movement. This quickly darkens down the room, and shows no signs of “pushing” fire through both video and thermal footage inside the interior stairwell. Soon after, another crew directs a wide fog stream toward the window of the opposite second-floor bedroom. This almost immediately creates a dramatic burst of thermal energy down the interior stairs, creating the appearance of the water “pushing” the fire to additional locations beyond the room of origin. As this video footage played out in the classroom, the instructor exclaimed something to the effect of “now you tell me that water doesn’t push fire!” Although certainly well-meaning, in this case the instructor missed the mark. Water doesn’t push fire. However, air will. What is shown in the video is simply a very quick and dramatic reversal of flow path created by the air associated with a wide fog stream. Putting a PPV fan on a long stick and putting it in front of the window would have had a similar effect! We have routinely taught students in rookie school for years about how much air can be moved with a wide fog stream out a window for the practice of hydraulic ventilation, but then seem to forget that the exact same is true in reverse. The water holds no blame in this scenario; only the air that the improperly formed outside stream brings with it, effectively sealing off the exhaust point with high-pressure air and causing the thermal energy, steam, and convective heat currents to rapidly find another lower-pressure outlet. Exterior water application is certainly an appropriate option for a quick initial attack under many circumstances, provided that it is immediately followed up with a rapid interior push to the seat of the fire. However, firefighters absolutely must understand and train on the specific method of water stream application, allowing the window opening to still maintain its status as an exhaust point while sneaking in some water to the ceiling level to momentarily reset the fire condition. Without these types of details and specifics, any operational strides gained by the research of the past few years will be quickly lost on the fire service with a few instances of poor application and the resulting adverse experiences on the fireground.