Some say only 1/5, others say 1/50 and others say 1/500 of the Israelites left Egypt. This means between 80-99.8% of Jews (the reshaim who did not merit or want the Redemption from Egypt) died, presumably in in the ninth plague (darkness).
Why did the prototypical
And he retorted, "Who made you a man, a prince, and a judge over us? Do you plan to slay me as you have slain the Egyptian?" Moses became frightened and said, "Indeed, the matter has become known!"
Moses became frightened: [To be explained] according to its simple meaning [that Moses was afraid Pharaoh would kill him]. Midrashically, it is interpreted to mean that he was worried because he saw in Israel wicked men [i.e.,] informers. He said, Since this is so, perhaps they [the Israelites] do not deserve to be redeemed [from slavery]. [From Tanchuma, Shemoth 10]
and recidivist (complainers during the Wilderness, Korach affair etc) reshaim Dathan and Abiram not die?