My question is what happened between when they went in the water and when they got off-site medical treatment. 7 hours seems like a long time. Is there on-site medical that would be doing something during that time?
Among other things, he had to sit inside an enclosure made of scintillator material for a period of time, to make sure he wasn't contaminated. Then he also got blood tests for heavy metals etc. They pretty much went by the book for all of these tests.
Also, the facility is the only place that's equipped for this kind of situation.