So in Booby Trap and Final Mission the Enterprise is bombarded with radiation. The obligatory countdown clock is added to the episode to increase tension and as always the crew fix things just in the nick of time - seconds to spare.
With radiation poisoning, surely they should be on the floor rolling around in agony and bleeding from every orifice by that point and face months of rehabilitation as 24th century medicine regenerates their body?
Assuming the countdown was missed and they got exposed to the lethal amount, do they just drop dead at zero? Or the week after? Or what...?