The robot sent into Fukushima to measure radiation levels called "Packbot" did actually measure more than 5 Sieverts/Hr. This is because the meter went overscale. And not only that, the radiation levels for the meter went overscale OUTSIDE the "train room" on the second floor.
Look at the radiation readings in the picture picked up by the "Packbot". The path that the robot took is trought an air