Radiation level measured from molten fuel?

There is a Japanese Self-Defense Force video of the Fukushima site taken from a helicopter in mid-March that shows what looks like a glowing molten blob of melted fuel apparently exposed somewhere on the roof of Reactor 1. The molten material is visible in a few frames of the video, and this video has been posted on YouTube by many people. The size of the blob is maybe about that of a large watermelon, maybe larger, although it is very hard to tell the size and location because of the way the video was shot (the camera-man may well have been shaking, and zoom is used).

One thing that is puzzling from Tepco's site radiation reports is the unusually high level of radiation measured outside the office buildings, which are some distance from the reactors, and there the radiation was measured at up to 2milliSv/h in mid-March. The office buildings are a few hundred meters NorthWest from Reactor 1. My question for the BRAWM team is how much radiation at say 300m would a blob of melted fuel of various sizes produce? Would a large watermelon size blob of exposed fuel be capable of producing 2milliSv/h at a few hundred meters distance?