I think there is a BIG difference between self-sacrifice & throwing one's life away.

the former implies nothing worthwhile came of it, while the latter is the very opposite. In the Atom goes to Mars episode, the officer (Ketchup) redeemed himself from his treachery in sabotaging Atom's umbilical cord or giving him a nearly empty energy cassette by leaping into a vehicle and charging straight into the enemy. Atom could not endure this act, because to him, the man intended to die or was heedless of the overwhelming odds. But because of this act, the tide turned against the enemy. Thus, though he may have been attempting suicide, he also because he was not worried about his own death, was that much more effective in his attack. If he had just run out there unarmed and yelled "shoot me! I cannot bear to live with the guilt of my treachery!" that would be throwing his life away, though it was obvious that he deserved death.
In the case of the current situation, these who decide do this work, though it means exposing themselves to lethal doses of radiation are not throwing their lives away. They are working to achieve a definite goal, one they acknowledge will cost the lives of those who pursue it. It is the choice of words that I find strange.