Flash-over is a special phenomenon indicating the critical point in the growing process of indoor fires. When flash-over occurs, the life of a person on the same floor and a relevant room is in danger, and the fire can spread throughout the building through the stairs between floors. As alarms that indicate emergencies are frequently malfunctioning, it is common that students on college campuses do not leave immediately when they hear a fire alarm siren. The aim of this study was to simulate flash-over points in the fire alarm metaverse. A smartphone’s temperature sensor showed sufficient detection capability to satisfy the accuracy of temperature survey equipment as required by the World Meteorological Organization (WMO) observation guidelines. The flash-over point metaverse built-in Roblox showed potential as an educational tool for fire disasters by enabling students to easily understand the mechanisms inherent in fire alarm sounds. This study can be an important reference as a fire disaster education instrument in an online game environment by presenting a metaverse’s potential in visually implementing the flash-over principle.