So here's a question - what if killing Tuvix to bring back Tuvok and Neelix would have no effect, but Our Heroes were able to determine that subjecting -someone else- to the procedure would restore them?
"Ensign Kim, you're less valuable than Tuvok and Neelix, so off you go."
Some people here seem to be faulting Tuvix for having a strong enough sense of self-preservation that he doesn't want to undergo a risky procedure that may yield no tangible gains. Would Random Crewman X be any more willing to sacrifice themselves in such circumstances?
Hell, would Janeway...or Kes...put their money where their mouths are?