What was the main issue that led to the early end of the school field trip?

The main issue that led to the early end of the school field trip was a fire threat that emerged nearby. This situation would have posed a significant risk to the safety of the students and staff, necessitating an immediate response to evacuate or relocate the group to ensure their protection. Fire threats can escalate quickly, leading to hazardous conditions, which makes prioritizing the well-being of individuals involved critical in such scenarios.

While factors like an unexpected visitor, a student becoming unwell, or bad weather conditions can also disrupt activities, the urgency and potential danger of a nearby fire threat would take precedence, making it the most compelling reason for concluding the trip prematurely.