I've discovered that this is an idea expressed quite a bit earlier than the Chafetz Chaim. The Ta"Z to YD 251:(6) says (commenting on the Psak of the Shulchan Aruch that one may use money designated for Talmud Torah to save people from being stripped and beaten)
<br><br>"The Rasha"l asks on this ... Gadol Talmud Torah MeHatzalas Nefashos... And there is no question here, for certainly there is nothing that overrides Pikuach Nefesh, only there the Gemara means that there is more merit to one who merits to learn Torah and did not have the opportunity to engage in Hatzalas Nefashos, than one who has the opportunity to save lives and through this he had to be Mevatel Torah and deal with Hatzalas Nefesh. This is learned from Mordechai Bilshan, that initially, where he did not have any opportunity to engage in Hatzalas Nefashos, he was more important in the eyes of the Chachamim than later, when he had the opportunity to perform Hatzalas Nefashos and he had to be Mevatel Torah, as it says there that the Chachamim did not count him as they did before."
<br><br>The Ta"Z goes on to prove this from the later comparison between Talmud Torah and Binyan Beis HaMikdash, where Ezra did not go up since the Mikdash was going to be built anyway, and Talmud Torah is greater than participation in that construction.
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