Why does the behaviorist account struggle to explain the meaning of the warning “Fire!”?

The behaviorist account, proposed by B.F. Skinner, defines the meaning of an utterance as the behavioral stimulus that triggers it, the response it produces, or a combination of both.1

This theory struggles to explain the warning "Fire!" because it implies that the meaning of the word changes based on the listener's reaction. For instance, if one person runs away upon hearing "Fire!" while a firefighter or a pyromaniac reacts differently, the behaviorist view is forced to conclude that the word has a different meaning for each individual. This is considered implausible, as it fails to account for the consistent, conventional meaning of the expression regardless of how a specific hearer chooses to respond.1

Furthermore, the behaviorist approach faces challenges regarding compositionality, as it cannot adequately explain how the meanings of complex expressions are derived from their individual parts if meaning is tied solely to observable behavioral responses.1