Let me echo what "productiveslacker" just just said. I had just explained almost exactly the same thing to some friends of mine who sent me the link.

Obviously pretty accurate for a building that has already vented through the roof (so it isn't pitch black from smoke). That's a pretty typical advancement with an inch and three quarter line by a reasonable crew without a great deal of experience (would be typical of most town fire departments). Our typical crew would look pretty much like that. If the right guys happened to be around, all our career guys who work in (neaby city) it would have happened much faster and with a lot less talking about it.