I'm rather confused by this ask; MTs are IoT sensors; they are not a management system in themselves - you can't send alerts to them. So the MT15 might well send it's own alert, if a fire happened to cause any one of the parameters it monitors to exceed a configured alert threshold. Bear in mind though - MT15 is not a smoke detector, nor is it designed for such 'life-and-death' use cases. This is why we describe it as an air quality sensor.
Bear in mind the MT sensors rely on the Meraki Dashboard (and interconnecting Meraki APs / MV cameras as BLE gateways) as the means to report on the parameters they measure. So, for example, if an MT15 detects that the temperature has exceeded a configured threshold, it alerts to the Dashboard in the first instance. This can also then result in emails or webhooks ecternally. This could also be supplemented via MQTT-based monitoring.