The doctors were surprised by the lack of preparedness of the Pripyat Medical Center for acute radiation sickness.
In particular, the lack of large-range radiometers meant that the players had no way of determining how much RAD of radiation they had absorbed in the previous explosion. This meant that they had no method of estimating how much time they had left.
However, the good news was that they had found potassium iodide injection in the hospital.
"The best time for this thing to take effect is before your exposure is to radiation. It is, however, still effective even after you are exposed to radiation." The doctor gave the players, including himself, an IV drip. WIth drip stands in hand, coupled with the hospital gowns, they looked no different from patients now.