What indicates a potentially dangerous situation during a fire emergency?

Leaning walls are a significant indicator of a potentially dangerous situation during a fire emergency. When walls begin to lean, it suggests a loss of structural integrity, often resulting from fire damage or prolonged heat exposure. This instability can pose a serious hazard to anyone in the vicinity, as the wall could collapse suddenly, leading to injury or fatalities.

In contrast, stable structural elements indicate safety and stability, while excessive smoke could signal danger but does not directly reflect structural integrity. Cool temperatures, on the other hand, would typically suggest that the fire is under control or has not yet impacted the area significantly. Thus, leaning walls directly correlate with an immediate and severe risk during a fire emergency.