. >> narrator: colonel shinji iwakuma and his team wore suits that shielded their bodies from radioactive particles, but provided no protection against lethal gamma rays. their mission was to inject water directly into the core of reactor three. >> (translated): just as we were about to get out of the jeep to connect the hose... it exploded. lumps of concrete came ripping through the roof of the jeep. radioactive matter was leaking in through the bindings of our masks. our dosimeter alarms were ringing constantly. >> narrator: the soldiers were now surrounded by lethally radioactive debris. they were injured in the blast, but managed to flee the scene before anyone received a fatal dose. >> (translated): i was desperate to get away from the danger. we were lucky on many levels. we were lucky. just lucky. >> narrator: parts of the nuclear plant were now completely off-limits to the workers. radiation levels near one of the reactor buildings were at 1,000 millisieverts per hour. after an hour of exposure at these levels, radiation sickness sets in. a few hours would mean death. >> (translat