Little MQTT project

I have ultrasonic sensor (sensor
1) connected to an ESP8266 and a Raspberry PI on the same WIFI network connected to another ultrasound sensor (sensor 2). When the distance detected by the sensor 2 is less than 30 cm, a movie starts on the RPI. I want that if a person passes in front of sensor 1 and then in front of sensor 2 the movie should not start. I want to use MQTT.