He had not been informed that there was another attempt at the rundown test that night.[1] While on a bus passing by the fourth reactor block, Bryukhanov realized the upper structure of the reactor was gone.[6][7] He ordered all authorities to meet at the nuclear bunker in the basement of the administration building.[2] Bryukhanov attempted to contact the shift supervisor but there was no answer at the fourth reactor block.[2] He then activated a General Radiation Accident on the automatic telephone system,[2] which sent a coded message to the Ministry of Energy.