At 3:20 p.m., the screwdriver slipped and the upper beryllium hemisphere fell, causing a "prompt critical" reaction and a burst of hard radiation. At the time, the scientists in the room observed the blue glow of air ionization and felt a heat wave. Slotin experienced a sour taste in his mouth and an intense burning sensation in his left hand. He jerked his left hand upward, lifting the upper beryllium hemisphere, and dropped it to the floor, ending the reaction. He had already been exposed to a lethal dose of neutron radiation. At the time of the accident, dosimetry badges were in a locked box about from the accident. Realizing that no one in the room had their film badges on, "immediately after the accident Dr. Slotin asked (Dr. Raemer E. Schreiber) to have the badges taken from the lead box and placed on the critical assembly". This peculiar response was of no value for determining the actual doses received by the men in the room and put Dr. Schreiber at “great personal risk” of additional exposure. A report later concluded that a heavy dose of radiation may produce vertigo and can leave a person “in no condition for rational behavior.”