There quickly comes a point called flashover in the life of a fire spreading inside a structure. Deadly, highly combustible gases build up from partial burning, and these gases soon fill the entire structure. Suddenly the pent-up heat ignites the gases with a whoosh and the fire is out of control--especially in an old wooden structure as this apparently was.
The structure was rapidly building toward flashover the moment the flames were spotted on the back wall. There was no time to spare at that point.
There was no time to spare at that point. Amen ... and this observant individual recognized it and acted.
There is little time to spare on the world stage right now and we must act with the same sense and urgency.