Комментарий к Бамидбар 16:33

AND THEY PERISHED FROM AMONG THE ASSEMBLY. The meaning thereof is that they [Korach and his associates] perished in their sight [that of the people], while they were standing amongst them in their midst, since the earth suddenly opened up its mouth and closed it upon them, and the place where they had been [standing] was not noticeable.¹⁶⁸See Nahum 3:17. And Rabbi Abraham ibn Ezra commented that the meaning of the expression is: [they were blotted out from among the assembly] because of the death of their children who would have been in their stead.

ותכס עליהם הארץ, the Torah emphasises that this phenomenon was unlike an earthquake in which the fissures in the earth do not close again to wipe out any traces of what had occurred. Here, the earth looked as if nothing had happened after Korach and his fellow travelers had disappeared.

וירדו…חיים שאולה, they descended into Sheol while still alive. The earth did not kill them but they remained alive so that the bowels of the earth became their Gehinom. The reason the Torah did not say חיים לשאול, but חיים שאולה is that although generally speaking when a word should have the letter ל at the beginning, the letter ה at the end of that word can substitute for the missing letter ל at the beginning, the Torah does not make such changes arbitrarily, without a reason. In this instance the Torah hinted by means of this construction that after Korach and associates descended they did not die but were given the ability to remain alive. This is what is meant by Sanhedrin 100 that G'd gives the wicked the ability to experience their punishment. If they were to die too soon they would not suffer the pain of G'd's retribution. If the Torah had written לשאול instead of שאולה, the meaning would have been that they died as soon as they arrived in Gehinom.